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Dissertations / Theses on the topic 'Reproductive endocrinology'

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Published: 4 June 2021
Last updated: 6 September 2023

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1

Walker, Susan Lorene. "Aspects of reproductive endocrinology in the red wolf (Canis rufus)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0032/MQ47373.pdf.

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2

Hector, J. A. L. "The comparative reproductive endocrinology of Diomedea Albatrosses at South Georgia." Thesis, University of Bristol, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354456.

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3

Kersey, David C. "Reproductive and adrenal endocrinology of the giant panda (Ailuropoda melanoleuca)." Fairfax, VA : George Mason University, 2008. http://hdl.handle.net/1920/3428.

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Thesis (Ph.D.)--George Mason University, 2008.
Vita: p. 180. Thesis director: Thomas C. Wood. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Environmental Science and Public Policy. Title from PDF t.p. (viewed Mar. 17, 2009). Includes bibliographical references (p. 156-179). Also issued in print.
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4

Walker, Susan Lorene. "Aspects of reproductive endocrinology in the red wolf (Canis rufus)." Connect to this title online, 1999. http://www.nlc-bnc.ca/obj/s4/f2/dsk1/tape2/PQDD%5F0032/MQ47373.pdf.

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5

Costas, Caudet Laura. "Reproductive factors, hormone use, and endocrine disruptors in the etiology of lymphoid neoplasms = Factors reproductius, ús d’hormones i disruptors endocrins en l’etiologia de les neoplàsies limfoides." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/565936.

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Lymphoid neoplasms are a heterogeneous group of cancers characterized by the neoplastic or clonal proliferation of lymphoid cells in different stages of differentiation. The incidence rate of these neoplasms has seen a rise in some western countries since the 1970s and it seems to have reached a plateau during the last decade. Incidence rates are higher in men than in women for most lymphoma subtypes; however, the causes explaining these differences by sex are unknown. We hypothetised that hormonal factors could have a role in lymphoma etiology. The general aim of this thesis was to assess the risk of lymphoid neoplasms in relation to reproductive factors and occupational exposure to endocrine disruptors. We used different studies and populations to evaluate our hypothesis: the EpiLymph study, the InterLymph consortium, the International Multiple Myeloma Consortium, and a systematic review. As well, we developed a new tool to estimate occupational exposures to a specific type of endocrine disruptors. We observed contradictory findings across studies and lymphoma subtypes concerning the association between lymphoma and parity, as well as hormonal contraceptives. We observed inverse associations between postmenopausal hormone therapy and lymphoma, although we noticed in our systematic review that cohort studies usually found null associations. We observed associations with lymphoma and prolonged (≥30 years) occupational exposure to endocrine disrupting chemicals, in particular for multiple myeloma and chronic lymphocytic leukemia. Associations were observed between lymphoma and prolonged occupational exposures to organic solvents, pesticides, brominated flame retardants, alkylphenolic compounds, and metals. To further explore the associations with alkylphenolic compounds, we developed a job-exposure matrix on these compounds considering relevant changes in use over time. In conclusion, our results indicate that reproductive factors and exogenous hormone use are unlikely to play a role in lymphomagenesis. The associations between occupational exposure to endocrine disrupting chemicals and lymphoma need to be further explored in studies using a more detailed exposure assessment.
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Othen, Leanne Stacey. "Reproductive endocrinology of wood bison during estrus synchronization, superovulation and pregnancy." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq24494.pdf.

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7

Dodson, S. E. "Reproductive endocrinology of the heifer from birth to the peripubertal period." Thesis, University of Nottingham, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376401.

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8

Nobrega, Rafael Henrique. "Alterações do epitelio germinativo masculino, celulas endocrinas testiculares e celulas gonadotropicas durante o ciclo reprodutivo de Serrasalmus spilopleura (Kner, 1859) e Pimelodus maculatus (Lacepede, 1803)." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/317613.

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Orientadores: Irani Quagio-Grassiotto, Maria Ines Borella
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-06T21:58:16Z (GMT). No. of bitstreams: 1 Nobrega_RafaelHenrique_M.pdf: 10312793 bytes, checksum: 13a65bc78504251ac2368131cd7f57fd (MD5) Previous issue date: 2006
Resumo: Nos peixes teleósteos, a unidade morfofuncional da espermatogênese é o espenrmatocisto ou cisto, constituído por células germinativas, em desenvolvimento sincrônico, envoltas perifericamente pelas células de Sertoli. Em função da cinética da espermatogênese e do tipo de reprodução (contínua ou sazonal), o epitélio germinativo pode se desenvolver de forma constante ou sofrer modificações cíclicas durante o ciclo reprodutivo. O presente trabalho teve como objetivo analisar, através de parâmetros histológicos, ultra-estruturais e imuno-histoquímicos, as alterações do epitélio germinativo em duas espécies de ciclos reprodutivos diferentes (Serrasalmus spilopleura - reprodução contínua e Pimelodus maculatus - reprodução sazonal) e correlacioná-las com as células esteroidogênicas e as células gonadotrópicas, no intuito de melhor compreender a fisiologia reprodutiva dos teleósteos tropicais de água doce. Em S. spilopleura, o epitélio germinativo organiza-se em cistos basais de espermatogônias e cistos apicais de células germinativas em desenvolvimento mais avançado. As espermatogônias basais apresentam intensa atividade proliferativa durante todo o ciclo reprodutivo. As células de Sertoli proliferam no intuito de acompanhar o crescimento dos cistos e aumentar o tamanho do testículo a cada ciclo reprodutivo. Quanto à esteroidogênese, a atividade 3"beta"-HSD é maior na região espermatogênica do que na região relacionada à espermiação. Em relação às células gonadotrópicas, as células LH são requeridas durante a espermatogênese e na espermiação, enquanto que as células FSH são mais ativas na liberação dos espermatozóides e provavelmente na proliferação das células sle Sertoli. Em P. maculatus, o epitélio germinativo passa por modificações morfofuncionais, categorizadas em quatro classes reprodutivas: regredida, maturação, maturação final e regressão. A proliferação das espermatogônias é intensa durante a maturação e depois diminui na maturação final e regressão. As células de Sertoli proliferam em maior freqüência na classe regredida, o que contribui para o crescimento do testículo durante o ciclo reprodutivo. A atividade 3"beta"-HSD é intensa na maturação e na maturação final, e depois diminui na regressão e na classe regredida. Os processos de espermatogênese e liberação de espermatozóides são dependentes de andrógenos. As células LH e FSH estão em maior quantidade durante a maturação e a maturação final, e depois diminuem na regressão e na classe regredida. A espermatogênese e a liberação dos espermatozóides são mais dependentes da atividade gonadotrópica do que os processos de proliferação espermatogonial e regressão testicular
Abstract: In teleost fish, the morphofuncional unit of the spermatogenesis is the spermatocyst or cyst, which are constituded by synchronous developmental germ cells surrounded by Sertoli cells. Depending on the spermatogenesis kinetics and the type of reproduction (continuous/non-seazonal or seazonal), the germinal epithelium may be constant or undego cyclical changes during the reproductive cyc1e. The aim, of the present work is to analyze, through histological, ultrastructural and immunohistochemical evaluation, the changes of the germinal epithelium in two different reproductive cycles (Serrasalmus spilopleura continuous/non-seazonal reproduction and Pimelodus maculatus - seazonal reproduction) and to correlate them with steroidogenic cells and gonadotropic cells, for a better knowledge on the reproductive physiology of the tropical fresh water teleosts. In S. spilopleura, the germinal epithelium was organized in basal cysts of spermatogonia and apical cysts of more advanced developmental germ cells. The basal spermatogonia had intense proliferative activity during the whole reproductive cycle. Sertoli cells proliferation occured in order to accompany the cyst growth and to increase the testis size during each reproductive cycle. For steroidogenic activity, 3"beta"-HSD was stronger in the spermatogenic area than in the area related to spermiation. In re1ation to gonadotropic cells, LH cells were requ~sted during spermatogenesis and spermiation, whereas FSH cells were more active in spermatozoa liberation and probably in the Sertoli celI proliferation. In P. maculatus, the germinal epithelium undergoes morphological changes, classified in 4 reproductive classes: regressed, maturation, final maturation and regression. The spermatogonial prolif~ration was intense during maturation and decreased in final maturation and regression. Sertoli cells proliferated more in regressed class, contributing to testis growth during the reproductive cycle. The 3"beta"-HSD activity was strong in maturation and final maturation, and decreased in regression and in regressed class. Then, spermatogenesis processes and spermatozoa release are dependent of androgenic. LH and FSH cells were in large number during maturation and final maturation, and decreased in regression and in regressed class. In P. maculatus, spermatogenesis and spermatozoa release are more dependent of the gonadotropic activity than the processes such as spermatogonial proliferation and testicular regression
Mestrado
Biologia Celular
Mestre em Biologia Celular e Estrutural
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9

Lovell, Tristan M. "Inhibin A, activin A and total inhibin #alpha#-subunit in the domestic fowl (Gallus domesticus)." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301897.

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10

Stamouli, Anna. "The effect of cytokines and lectins on the epidermal growth factor response of breast and ovarian cancer cells." Thesis, University of Southampton, 1995. https://eprints.soton.ac.uk/394156/.

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11

Campbell, Pamela Mary. "The effects of stress on the reproductive endocrinology and gamete quality of trout." Thesis, Brunel University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306723.

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12

Edelstein, Sascha. "Familial association of polycystic ovary syndrome (PCOS) in women attending the gynaecological endocrinology clinic at Groote Schuur Hospital." Master's thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/10437.

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Includes bibliographical references (leaves 60-65).
Polycystic ovary syndrome (PCOS) is the commonest endocrinopathy in women of reproductive age, affecting 5-10% of women in the general population. Patients present with menstrual disturbances, infertility and clinical hyperandrogenism. While the pathophysiology is not completely delineated, a strong familial association has been demonstrated, suggesting a genetic component. From January 2007 until February 2009, a total of 83 probands were recruited from the Gynaecological Endocrinology Clinic (GEC) at GSH. These were all women with PCOS according to the Rotterdam criteria who presented for management at the GEC. With their consent, first degree female family members were contacted and 57 mothers, 108 sisters and 8 daughters agreed to participate in the study.
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13

Gallipeau, Sherrie. "Altered Reproductive Function and Amphibian Declines." Thesis, University of California, Berkeley, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3640434.

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Agrochemical exposure is one of the factors that contributes to worldwide amphibian declines. Most studies that examine agrochemicals and amphibian declines focus on toxicity. However, declines are more likely caused by the sub-lethal effects of agrochemical exposure. Past emphases on the lethal effects of agrochemical exposure have overshadowed the contribution of decreased recruitment in amphibian declines. Additionally, studies that examine agrochemicals and reproductive function tend to focus on the effects of single chemical exposures instead of the effects of ecologically relevant mixtures. To address these issues, this dissertation examined the effects of ecologically relevant agrochemical exposures on the stress response and the reproductive endocrinology, morphology, and behaviors of male amphibians in the laboratory and the wild.

Chapter 1 provides a general review of the factors implicated in amphibian declines and provides an overview of the previous research conducted on the effects of agrochemical exposure on recruitment.

Chapter 2 is a field study that examined whether agricultural run-off alters the stress response and reproductive function of male bullfrogs ( Lithobates catesbeianus). Bullfrogs were collected upstream and downstream of agricultural activity across three California river systems (Salinas, Sacramento and San Joaquin). Size, primary and secondary sex traits, sperm count, and corticosterone and testosterone levels were examined. Overall, bullfrogs living downstream of agricultural activity (i.e. exposure to agricultural run-off) were small and had elevated testosterone and corticosterone levels. In addition, downstream males from the Salinas and San Joaquin Rivers were also small in size and had elevated testosterone levels. However, only downstream males of the San Joaquin River had elevated corticosterone and exaggerated secondary sex traits. Together, these data suggest that living downstream of agriculture can alter size, hormone levels, and the expression of sexually dimorphic sex traits. Such changes to the reproductive endocrinology and morphology of male amphibians can be detrimental to the reproductive health and long-term reproductive success of amphibian populations.

In Chapter 3, I examined corticosterone, testosterone, and the reproductive clasping behaviors of adult male African clawed frogs (Xenopus laevis) exposed to field collected and simulated agricultural run-off. This experiment implemented a novel eco-relevant experimental design to mimic real-life agrochemical exposures. Male frogs were exposed to field water collected downstream (agricultural run-off) and upstream (negative control) of agricultural activity along the Salinas River, CA. In addition, a pesticide mixture containing the top agrochemicals used in the Monterey County was included to simulate agricultural run-off. Mating behavior was suppressed in males exposed to simulated agricultural run-off but enhanced in males exposed to field collected agricultural run-off. In addition, testosterone levels of clasping males were elevated in comparison to controls. Males immersed in simulated agricultural run-off had significantly lower testosterone levels than control males in 2010. These data suggest that agrochemical exposure (both field collected and simulated) can alter reproductive hormones and clasping behaviors. Altered sex hormones and behaviors in male amphibians may play a role in amphibian declines.

Lastly, this dissertation is summarized in Chapter 4. The applicability of this dissertation as a model for amphibian declines and other reproductive related human health concerns are also introduced.

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Coward, Kevin. "Aspects of the reproductive biology and endocrinology of the substrate-spawning cichlid Tilapia zillii." Thesis, University of Stirling, 1997. http://hdl.handle.net/1893/415.

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This study investigated several, previously little-known, aspects of reproductive physiology and endocrinology in the substrate-spawning cÌchlid Tilapia zillii; a tilapia that is becoming increasingly popular in world aquaculture. Studies were undertaken in controlled laboratory aquaria, thereby reducing the potential influence of environmental variation evident in many previous field studies of this species. Analysis involved two strains of T. zillii: strain 'A' (T. zillii) and strain 'B' (formerly known as Tilapia tholloni). Spawning periodicity and total fecundity generally increased with fish size. Egg size varied within a narrow window and did not generally increase with fish size though fish weighing 100 - 200g tended to produce the largest eggs. The best estimate of spawning periodicity was considered to be 'mean days elapsed/spawn' as this figure was based upon both spawning and non-spawning fish in an experimental group. Mean days elapsed/spawn increased with increasing fish size and averaged 61.4 days and 37.5 days in strains 'A' and 'B' respectively. The shortest reproductive cycles observed were just 7 days and 6 days for strains 'A' and 'B' respectively. Total fecundity ranged from 461 - 11640 eggs/clutch. Mean total fecundity was 3606+/-280 in strain 'A' and 3560+/-243 in strain 'B'. Mean egg diameter was 1.5+/-0.04mm and 1.4+/-0.08mm in strains 'A' and 'B' respectively. Fecundity and egg size also varied over successive spawns in serial-spawning females but these variations did not appear to be related to spawning periodicity. Regression analysis revealed strong relationships between fish size (weight and length) and total fecundity, relative fecundity and total egg volume. Relationships between fish size and egg size were generally much weaker. Fecundity and egg size were related to the length of the preceding inter-spawn-interval (ISI) in fish of certain weight categories but not others, providing limited evidence that length of ISI may in par, control fecundity and egg size in this species. Ovarian recrudescence was classified into ten distinct developmental stages based upon oocyte size, biochemical properties and structure. This classification scheme was comparable to classification schemes developed for other teleosts but represents the first detailed description of oocyte growth in a substrate-spawning tilapia. Radioimmunoassay and stereological analysis provided valuable and novel data concerning the dynamics of ovarian development in this species. Levels of 17ßoestradiol (E2) and testosterone (T) peaked within 6 days of spawning, suggesting that vitellogenesis began as early as day 2 or 3 post-spawning. By day 8, ovaries were dominated by large late-vitellogenic/maturing oocytes (stages 6 & 7) occupying 60 - 70% of the ovary. Gonadosomatic index (GSI) reached maximal levels by day 14. Since the proportion of stage 6/7 oocytes exhibited little change from day 8 onwards, it is suggested that pre-vitellogenic oocytes are recruited into vitellogenic growth immediately after spawning and complete vitellogenesis as early as day 8 postspawning. Analysis of serial-spawning fish found that initial post-spawn E2 and T peaks (on days 2 - 6) were much lower after the second spawning. Sex steroid levels were also found to be suppressed in confined T. zillii (i.e. where stocking densities were > lOkg/m3). Confined females failed to spawn but displayed a marked tendency to do so after transfer to individual aquaria. Serum E2 and T were suppressed during confinement but increased rapidly following transfer to individual aquaria (coincident with resumed spawning activity). It is suggested that levels of E2 and T under confinement are not sufficient to allow completion of vitellogenic growth and are most probably suppressed via a pheromonal mechanism. Finally, the present study investigated the effect of prolonged food restriction on various aspects of reproduction. T. zillii were rationed from first feeding and throughout the following 17 months. Despite very large differences in fish size, no significant differences were detected in total fecundity, egg diameter nor total egg volume once data had been adjusted for differences in fish size. These data suggest that despite very large differences in food availability throughout the periods of sexual differentiation and on-growing, investment in reproduction remained relatively consistent. It appeared that during food restriction, T. zillii sacrificed body weight and growth so as to maintain reproductive investment. In summary, this study provides valuable and novel information regarding the reproductive physiology and endocrinology of female T. zillii and suggests that this species may be a suitable 'model' species for future work on fecundity and ovarian development.
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Abraham, Eytan. "Studies on reproductive biology and endocrinology in a primitive teleostei, the American shad (Alosa sapidissima)." College Park, Maryland : University of Maryland, 2004. http://hdl.handle.net/1903/1725.

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Thesis (M.S.) -- University of Maryland, College Park, 2004.
Thesis research directed by: Marine, Estuarine, Environmental Sciences. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Larkin, Iskande Lieve Vandevelde. "Reproductive endocrinology of the Florida manatee (Trichechus manatus latirostris) estrous cycles, seasonal patterns and behavior /." [Florida] : State University System of Florida, 2000. http://purl.fcla.edu/fcla/etd/ana6262.

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Thesis (Ph. D.)--University of Florida, 2000.
Title from first page of PDF file. Document formatted into pages; contains xv, 339 p.; also contains graphics. Vita. Includes bibliographical references (p. 319-338).
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Fazio, Jilian M. "Assessment of adrenal activity and reproductive cycles during captive management in the fishing cat (Prionailurus viverrinus)." Thesis, George Mason University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10140296.

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Fishing cats (Prionailurus viverrinus) are a small felid found primarily throughout Southeast Asia. Wild populations have been rapidly dwindling due to degradation and loss of habitat along with retribution killings. Captive populations have been established throughout the world to help ensure this species persists. In North America, Species Survival Programs (SSP) are committees formed within the Association of Zoos and Aquariums (AZA) to help manage captive populations of threatened and endangered species. The SSPs are made up of a group of species-specific experts dedicated to sustaining a healthy captive population that can serve to educate the public and potentially replenish dwindling wild populations if needed in the future. The SSPs make breeding recommendations for each species based on genetics, age and keeper intuition. Often because of a genetically valuable animal’s age, there is only one chance to create a successful breeding pair. It was hypothesized that individual fishing cats would differ in their adrenocorticol response during transfer between institutions and during breeding introductions. The prediction was that glucocorticoid levels would have a direct correlation with the manner in which the individuals are managed and overall breeding success.

The study ultimately had four objectives: 1. Examine the current management and breeding behaviors of captive fishing cats. 2. Validate a glucocorticoid assay for longitudinal monitoring of exogenous stressors on adrenocortical activity in males and females. 3. Determine relationship between adrenal activity and gonadal function in females. 4. Characterize temperament within the population and correlate with behavioral traits, breeding success and adrenal activity.

The study ran from 2010-2013 monitoring 27 (13 male; 14 female) fishing cats at 17 institutions which included 15 unique breeding pairs and 20 transfers (13 males, 7 females), which occurred primarily in the fall (62%). Validation of a single antibody cortisol enyzme immunoassay (R4866 supplied by C.J. Munro, University of California, Davis, CA, USA) was performed using standard assay validation. In addition, an adrenocorticotropin challenge revealed peak glucocorticoids metabolites (GCM) occur approximately 21 hours after adrenal stimulation. Longitudinal monitoring revealed significant elevations in GCM concentrations during institutional transfers lasting 54 ± 16 days indicating most individuals take at least three months to settle into a new facility after translocation. Most initial physical breeding introductions during this study (83%) occurred within that timeframe. Mate compatibility seems rigid with pairs copulating between 39-289 days after quarantine release, or not at all, indicating a one year trial period for pairs is sufficient to determine potential breeding success. Increases 4-10x in baseline GCM concentrations were observed during periods of chronic illness (i.e. hepatitis) and therefore could be used to help diagnose acute health concerns in this species.

Reproductive activity occurred throughout the year and was not impacted by institutional transfers. Natural pregnancies (n = 5) all occurred March-July and 67% of females exhibited one or more periods of anestrus lasting 66-181 days beginning most often April-August (67%). Highest mean progestogen and estrogen concentrations occurred between December and August. Differences in peak estrogens, occurring approximately 8 days (range 0-30) into non-pregnant luteal phases (NPLP) and 40 days (range 32-49 days) into a pregnancy may help distinguish the two. A high percentage of females (58%) exhibited spontaneous ovulation during the study period with no clear ovulation mechanism. Ovulation may be influenced by age or induced by external stimuli, other than intromission during copulation - such as semiochemicals detected in shared enclosure spaces or tactile contact through mesh enclosures. The species high reliance on aquatic habitats also may lend itself to resource dependant stimulation of the hypothalamus pituitary gonadal axis, such as annual rainfall or access to large pools of water, which bears further investigation.

Recommendations include transfers in the late spring or early summer of males allowing at least three months post quarantine release for physical introductions, to allow the tranferred individual time to return to baseline GCM concentrations before experiencing another stressful event (breeding introductions). Institutions with breeding pairs can improve breeding success via reducing fishing cat stress levels with positive animal keeper interaction through training and providing indoor off-exhibit refuge areas. It is also suggested that videotaping breeding introductions and providing at least 1-2 nest boxes for females may all contribute to greater captive breeding success in the fishing cat.

The information gained by this study provides an outline for fishing cat SSP managers on how this species is managed in captivity. It also provides a solid foundation of longitudinal monitoring of adrenal activity and provides recommendations for the future sustainability of the ex situ population. (Abstract shortened by ProQuest.)

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Miller, David Andrew. "Reproductive ecology of the mourning dove large-scale patterns in recruitment, breeding endocrinology, and developmental plasticity /." [Ames, Iowa : Iowa State University], 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3389128.

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Ljungvall, Karl. "Prepubertal exposure to Di(2-ethylhexyl) Phthalate : kinetics and effects on the reproductive system of the boar /." Uppsala : Dept. of Clinical Sciences, Swedish University of Agricultural Sciences, 2006. http://epsilon.slu.se/200615.pdf.

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Ferasyi, Teuku Reza. "Mathematical model of the reproductive endocrine system in male sheep." University of Western Australia. School of Animal Biology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0080.

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[Truncated abstract] The activity of the reproductive endocrine axis is the result of interactions among many organs and tissues, particularly the hypothalamus, pituitary gland and gonad. However, it depends on more than the communication between anatomical structures because it is also affected by genotype, internal factors (e.g., metabolic inputs) and external factors (e.g., photoperiod, socio-sexual cues, stress, nutrition). This multifactorial complexity makes it difficult to use animal experimentation to investigate the pathways and mechanisms involved. Therefore, in this study, I have turned to mathematical modelling. The general hypothesis was that, by modelling the hormonal feedback loop that links the hypothalamus, pituitary gland and gonad, I would be able to discover the critical control points in this homeostatic system. This would allow me to inform and direct research into the processes that control reproduction, including inputs from environmental factors. My studies began with the development of a model of the negative feedback loop through which testosterone controls the secretion of pulses of gonadotrophin-releasing hormone (GnRH) by the hypothalamus. The model incorporated two critical factors: testosterone concentration and a time delay in the inhibition of the activity of the GnRH 'pulse generator' by testosterone. The general assumptions were: i) there are two positive feedforward processes (GnRH pulses stimulate LH pulses, and, in turn, LH pulses stimulate testosterone secretion); ii) testosterone exerts negative feedback that reduces the frequency of GnRH pulses. The model incorporated a group of equations that represent the GnRH pulse generator, through which the inhibitory effect of testosterone acted to reduce GnRH pulse frequency. Simulations were run with various values for the time delay in feedback and, as model development progressed, the simulations were extended to include combinations of time delays and levels of sensitivity of the GnRH pulse generator to inhibition by testosterone. The output of the simulations showed clearly that a time delay in negative feedback, as well as the concentration of testosterone, can greatly affect the frequency of GnRH pulses and the shape of the GnRH secretory profile. Importantly, the effect of the time delay depends on the sensitivity of the pulse generator to testosterone. In addition, the simulations suggested two additional components that might be involved in the control of the GnRH pulse generator: i) a delay in the rate of adaptation to a change in steroid feedback; and ii) a minimum pulse interval (maximum frequency). These studies iii therefore suggest that the regulation of the activity of the GnRH pulse generator, and thus the frequency and profile of GnRH and LH pulses, requires interactions among these four components. These interactions should be tested in animal experimentation. In the next stage, I extended the model so I could test whether the feedback delay might involve the process of aromatization in which testosterone is converted to oestradiol at brain level. ... This information can be used to direct future experimental studies that will help us to understand the factors that underlie the dynamic behaviour of the hypothalamic and pituitary systems that control reproduction.
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Rafaela, Sayuri Cicalise Takeshita. "Factors regulating steroid hormones in Japanese macaques and orangutans." Kyoto University, 2018. http://hdl.handle.net/2433/232299.

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付記する学位プログラム名: 霊長類学・ワイルドライフサイエンス・リーディング大学院
Kyoto University (京都大学)
0048
新制・課程博士
博士(理学)
甲第20964号
理博第4416号
新制||理||1634(附属図書館)
京都大学大学院理学研究科生物科学専攻
(主査)准教授 Michael Alan Huffman, 准教授 足立 幾磨, 教授 友永 雅己
学位規則第4条第1項該当
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Castro, Ana Mafalda Lopes Sardica Velez de. "Mexican gray wolf courtship and mating : behavior & basic endocrinology during breeding season." Master's thesis, Universidade de Lisboa. Faculdade de Medicina Veterinária, 2016. http://hdl.handle.net/10400.5/11368.

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Dissertação de Mestrado Integrado em Medicina Veterinária
The Mexican gray wolf is the rarest subspecies of gray wolf in North America. It is officially “endangered” and its survival relies on good captive management and breeding programs. The present study’s main purpose is behavior evaluation and hormonal profile assessment during proestrus and estrus, in this species. Behavioral data and feces were obtained during the breeding season at the Endangered Wolf Center, and analyzed at the Saint Louis Zoo. Several behaviors presented moderate correlations. Differences were found between the frequencies of some behaviors in the pre and post conception periods. The average number of days between first detected Mount and first Copulatory Tie was three. Most frequent behaviors were described as well. A progesterone peak, associated with the onset of estrus, often coincided with the occurrence of Mounts and Copulatory Ties. Our predictions for conception dates were mostly in agreement with the existing hormonal data. These observations can be a basis for future reproductive situations – they allow for a better estimate of the ideal timing for Artificial Insemination and they add knowledge on reproductive patterns that characterize the breeding season of this species.
RESUMO - REPRODUÇÃO EM LOBOS MEXICANOS - COMPORTAMENTO & ENDOCRINOLOGIA BÁSICA DURANTE A ÉPOCA REPRODUTIVA - O lobo cinzento Mexicano é a subespécie mais rara de lobo cinzento na América do Norte. É oficialmente considerado "em perigo" e a sua sobrevivência depende de bons programas de gestão e reprodução em cativeiro. O principal objetivo deste estudo foi a avaliação do comportamento e perfis hormonais, durante o proestro e estro, nesta espécie. Os dados sobre comportamento e hormonas foram obtidos durante a época de reprodução, no Endangered Wolf Center, e analisadas no Jardim Zoológico de Saint Louis. Vários comportamentos apresentaram correlações moderadas. Também foram encontradas diferenças entre as frequências de alguns comportamentos nos períodos pré e pós-conceção. O número médio de dias entre a primeira “monta” e cópula detetadas foi três. Os comportamentos mais frequentes foram descritos. Um pico de progesterona, associado ao início do estro, coincidiu frequentemente com a ocorrência de montas e copulação. As previsões efetuadas das datas de conceção estiveram, geralmente, de acordo com os dados hormonais existentes. Estas observações podem vir a permitir uma melhor estimativa do momento ideal para Inseminação Artificial e acrescentam conhecimentos sobre os padrões reprodutivos que caracterizam a época reprodutiva desta espécie.
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23

Candeias, Isis Zanini das. "Monitoramento não invasivo da ciclicidade ovariana em Lycalopex vetulus." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/10/10131/tde-17032015-094340/.

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Devido as atuais mudanças globais é esperado que um grande número de espécies necessitem de uma integração de ações dentro e fora do seu ambiente natural para a conservação. O bioma cerrado é um dos ecossistemas mais ricos em biodiversidade, mas devido a ação antrópica, resta menos de 20% de sua cobertura vegetal original. A Raposinha do Campo (Lycalopex vetulus) é um canídeo de pequeno porte (2,5-4kg) endêmico do cerrado do Brasil central e está presente na lista dos animais ameaçados de extinção do Estado de São Paulo. Não existe em literatura uma descrição detalhada do ciclo estral desta espécie. O presente estudo teve como objetivo caracterizar a ciclicidade ovariana de Lycalopex vetulus com o uso de método não-invasivo: Extração e mensuração de metabólitos fecais de progesterona e estradiol, com o uso da técnica de enzimaimunoensaio, verificando também a possível existência de diferenças mensais entre as médias das concentrações dos referidos metabólitos em um período de 12 meses. Foram utilizadas 8 fêmeas, adultas, presentes em cinco instituições no estado de São Paulo, onde foram coletadas fezes 3 vezes por semana de cada indivíduo, durante 12 meses, para a extração e mensuração dos metabólitos de progesterona, estradiol e corticosterona. Os perfis das excreções dos metabólitos fecais dos hormônios sexuais de 6 das 8 fêmeas, foram muito semelhantes, sendo período de maior atividade reprodutiva entre os messes de julho, agosto e setembro, ocorrendo mais de um ciclo ovulatório dentro desse período. Nos outros meses do ano, apesar de algumas variações acima da linha basal, não foram encontrados indícios de atividade reprodutiva. De acordo com essas características, semelhante entre a maioria das fêmeas do estudo, podemos sugerir que a raposa-do-campo seja poliestrica sazonal, com atividade reprodutiva ocorrendo nos meses de julho, agosto e setembro. Esses achados são muito próximos do visualizado em populações de vida livre, onde acasalamentos são observados entre junho e julho. O perfil de excreção dos metabólitos fecais de glicocorticóides segue o mesmo padrão observado para os metabólitos de progesterona e estradiol, com um aumento mais significativo da excreção nos meses de julho, agosto e setembro. Esses resultados indicam que além da grande quantidade de estressores que podem alterar a excreção de glicocorticóides, também deve-se considerar a flutuação sazonal e o status reprodutivo do indivíduo ao avaliar as concentrações de metabólitos de glicocorticóides. Duas fêmeas, que dividem o mesmo recinto, não apresentaram um padrão de ciclicidade reprodutiva. Os resultados obtidos nesse estudo indicam que a dosagem de metabólitos fecais de progesterona e estradiol podem ser usadas para diferenciar o período reprodutivo do período não reprodutivo em fêmeas de Lycalopex vetulus, fornecendo informações importantes sobre a biologia reprodutiva da espécie, o que pode contribuir no desenvolvimento de estratégias para a conservação desta espécie, como por exemplo aumentar o sucesso reprodutivo ex situ.
Due to the current global changes is expected that a large number of species require an integration of actions inside and outside their natural environment for them conservation. The cerrado is one of the richest ecosystems in biodiversity, but due to human action, there remains less than 20% of its original vegetation cover. The Hoary fox (Lycalopex vetulus) is a small canid (2,5-4kg) endemic of the cerrado from the central Brazil and is present in the list of endangered species in the state of São Paulo. It was not found in literature any detailed description of the estrous cycle of this species. The present study aimed to characterize ovarian cyclicity in Lycalopex vetulus using a noninvasive method: Extraction and measurement of fecal metabolites of estradiol and progesterone, using the technique of enzymeimmunoassay, It was also verified the possible differences between the monthly mean concentrations of these metabolites in a period of 12 months. 8 captive adult females, were studied in five different institutions in the state of São Paulo, where feces were collected three times per week for each individual for 12 months for extraction and measurement of metabolites of progesterone, estradiol and glucocorticoids. The profile of the concentration of fecal metabolites of sexual hormones from 6 of 8 females was very similar, being the period of major reproductive activity between the months of July, August and September, with the occurrence of more than one ovulatory cycle within that period. In the others months of the year, despite some variations above the baseline, no evidence of reproductive activity were found. According to these characteristics, similar in most females of the study, we can suggest that the hoary fox is seasonal polyestrous with reproductive activity occurring in the months of July, August and September. These findings are very close to the observed in wild populations, where mating is observed between June and July. The profile of excretion of fecal glucocorticoid metabolites follows the same pattern observed for the metabolites of progesterone and estradiol, with a more significant increase in excretion in the months of July, August and September. These results indicate that besides the large amount of stressors that can alter the excretion of glucocorticoids also it must be considered the seasonal fluctuation and the reproductive status of the individual to evaluate the levels of glucocorticoids. Two females, who share the same captivity, did not show a pattern of reproductive cyclicity. The results of this study indicate that the dosage of fecal metabolites of estradiol and progesterone can be used to differentiate the reproductive period of non-reproductive period in females of Lycalopex vetulus, providing important information about the reproductive biology, which may contribute to the development of the species conservation strategies, such as increasing the reproductive ex situ success.
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24

Altmieme, Zeinab. "The Role of Nonapeptides in Male Reproduction in Two Cyprinid Species, the Zebrafish (Danio rerio) and the Goldfish (Carassius auratus)." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/38911.

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Two distinct nonapeptide systems, consisting of the vasotocin- and oxytocin-related peptides have evolved in vertebrates, and their role in male reproduction is well-described in mammals. In contrast, their comparative role in reproduction in basal vertebrate species, and teleost fishes in particular, has not been investigated in great detail. Using two cyprinid species, the zebrafish (D. rerio) and the goldfish (C. auratus), I address the hypothesis that the teleost nonapeptides vasotocin and isotocin stimulate male cyprinid reproductive physiology by affecting central neuronal and/or peripheral endocrine pathways. To test this hypothesis in zebrafish, an indeterminate breeder, I conducted pharmacological inhibition experiments employing vasotocin and isotocin-specific antagonists in males, a treatment predicted to inhibit reproductive success in mating trials. Because nonapeptides can act both as central peptide neuromodulators and as secreted hormone, I further quantified indices of male courtship behavior (nudging, circling and chasing) and major androgens (testosterone and 11-keto-testosterone) as key endocrine indices of the male reproductive axis. Together, these experiments revealed a dose-dependent, differential inhibition of spawning success, with significant reductions (-65%) in egg fertilization rate observed in pairs in which males had been i.p. injected with 5 ng/g vasotocin and significant reductions (-79%) observed at 500 ng/g i.p injected isotocin. In either case, these partial inhibitions of reproductive success were correlated with significant decreases in specific indices of male courtship behavior, but not endocrine indices, suggesting that individual nonapeptides mediate their effects via central modulation of behavioural neurocircuits. Interestingly, a co-administration of vasotocin and isotocin antagonists completely abolished reproductive success, however this effect was neither correlated with decreases in male courtship behavior, nor endocrine indices, suggesting a separate mode of action, possibly at the level of male pheromone release. To further probe the role of nonapeptides in male zebrafish reproduction, I subsequently tested the hypothesis that nonapeptide systems are acutely activated by key reproductive cues, specifically the releaser pheromone PGF2α, which serves as a chemoattractant and acutely stimulates male reproductive behavior in male cyprinids. Using a chemoattractant choice assay in conjunction with immunohistochemistry and gene expression approaches, I determined whether male zebrafish are attracted to pheromonal cues and acutely activate isotocinergic neurons in the short term and/or regulate nonapeptide gene expression in the longer term. My results show that individual male zebrafish are attracted to PGF2α in an acute choice test. Furthermore, an increase in p-ERK immunoreactivity, a marker of neuronal activation, was observed in the olfactory bulb 10 min following exposure, suggesting a specific response to the pheromone compared to EtOH vehicle. However, no co-localization of p-ERK and IT-positive perikarya was observed in the preoptic area (POA), refuting the hypothesis that PGF2α exposure acutely activates isotocinergic neurons in zebrafish. Analysis of whole brain relative mRNA transcript abundance revealed that PGF2α exposure time-dependently regulates whole brain isotocin, but not vasotocin transcript abundance, suggesting secondary longer-term effects of PGF2α exposure on the isotocinergic system. Using an analogous experimental approach, I further tested the hypothesis that nonapeptides stimulate male reproductive physiology in goldfish, a determinate breeder. Sexually mature male goldfish pretreated with saline or vasotocin or isotocin antagonists were exposed to saline or PGF2α-injected stimulus females and male courtship behavior (chasing, circling), endocrine indices (circulating testosterone) and milt release were quantified. Both nonapeptide antagonists reduced strippable male milt quantity in response to PGF2α-injected females, suggesting a neuronal or hormonal action of both nonapeptides on goldfish milt release. Together, I show that nonapeptides contribute to male reproductive physiology in two species of cyprinids with different reproductive tactics. However, the mode of action may differ from one species to another, with evidence suggesting that nonapeptides play a role in the regulation of reproductive behavior and, possibly, male pheromone, release in zebrafish, while effects on male goldfish seem to be exclusively related to the release of milt. Future studies should compare other teleost species with specific reproductive biology and focus on the gonadal roles of nonapeptides in sperm maturation and/or release.
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25

Brown, Amanda. "The Reproductive Biology of the Finetooth Shark, Carcharhinus isodon, in the Northwest Atlantic Ocean." UNF Digital Commons, 2015. http://digitalcommons.unf.edu/etd/564.

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Shark fisheries are a multimillion dollar industry in the United States and have significant contributions both recreationally and commercially. In order to maintain this industry, fisheries must be properly managed. An understanding of life history and reproduction is crucial in order to adequately manage shark fisheries. The finetooth shark, Carcharhinus isodon, is a member of the small coastal shark (SCS) fishery complex. It is found in Atlantic waters from South Carolina to Florida and throughout the Gulf of Mexico. This species has recently come under increased fishing pressure and has previously been overfished. New data is needed in order to properly assess the reproductive capacity of this species so that healthy populations can be sustained. This study evaluated the overall reproductive cycle of northwest Atlantic populations of C. isodon using composite variables of morphology, histology and endocrinology. Atlantic C. isodon were found to display seasonal reproduction with biennial reproductive periodicity with a 12 month gestation period and litters of 2-6 pups. E2 and T displayed similar patterns and were highest during gametogenesis. P4 did not show any discernible patterns. Estrogen receptors were found in developing follicles of gravid and non-gravid females, in the oviducal glands of non-gravid and early pregnant females and in the uterus of pre-ovulatory females. P4 was found in the oviducal glands in all reproductive stages and in the uterus of pre-ovulatory females. Androgen receptors were found in Sertoli cells and mature spermatozoa as well as epididymal epithelial cells.
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26

McMillan, Hugh John. "Peripheral changes in levels of progesterone and prolactin during reproduction in the Siberian hamster, Phodopus sungorus, evidence for both conservation and rapid evolution of reproductive endocrinology over evolutionary time." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq22352.pdf.

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27

Fürtbauer, Ines [Verfasser], Julia [Akademischer Betreuer] Ostner, and Peter [Akademischer Betreuer] Kappeler. "The socio-endocrinology of female reproductive strategies in wild Assamese macaques (Macaca assamensis) / Ines Fürtbauer. Gutachter: Julia Ostner ; Peter Kappeler. Betreuer: Julia Ostner." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2011. http://d-nb.info/1044247673/34.

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28

Fürtbauer, Ines Verfasser], Julia [Akademischer Betreuer] Ostner, and Peter M. [Akademischer Betreuer] [Kappeler. "The socio-endocrinology of female reproductive strategies in wild Assamese macaques (Macaca assamensis) / Ines Fürtbauer. Gutachter: Julia Ostner ; Peter Kappeler. Betreuer: Julia Ostner." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2011. http://nbn-resolving.de/urn:nbn:de:gbv:7-webdoc-3116-4.

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29

Lobago, Fikre. "Reproductive and lactation performnace of dairy cattle in the Oromia Central Highlands of Ethiopia : with special emphasis on pregnancy period /." Uppsala : Dept. of Clinical Sciences, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/2007121.pdf.

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30

McGee, Marcus. "The use of non-invasive monitoring techniques for profiling hormonal changes associated with stress and reproductive cyclicity in domestic and non-domestic species." Master's thesis, Mississippi State : Mississippi State University, 2009. http://library.msstate.edu/etd/show.asp?etd=etd-02102009-145608.

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31

Бойко, А. О., and М. М. Купрієнко. "Застосування імуногістохімічних реакцій в сучасній ендокринології репродуктивної системи жінок." Thesis, Сумський державний університет, 2015. http://essuir.sumdu.edu.ua/handle/123456789/41839.

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Репродуктивна система знаходиться під безпосереднім впливом гіпоталамо-гіпофізарної системи. У гіпоталамусі синтезується і секретується гонадотропін-рилізинг-гормон (рилізинг- гормон лютеінізуючогого гормону, гонадоліберину). Гонадотропіни - лютеїнізуючий і фолікулостимулюючий гормони - стимулюють розвиток і функціонування статевих залоз, статеве дозрівання, регулюють репродуктивну функцію. Порушення регуляції гіпоталамо- гіпофізарно-гонадотропної функції в дитячому та підлітковому віці лежить в основі синдрому затримки статевого розвитку або передчасного статевого дозрівання. У порівнянні з класичними гістологічними і гістохімічними забарвленнями методи імуногістохімії дозволяють з високою вибірковістю виявляти і локалізувати в тканинах, клітинах і внутрішньоклітинних структурах молекулярні компоненти, що володіють антигенними властивостями.
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32

Meikle, Ana. "Reproductive endocrinology of prepubertal and anestrous ewes : regulation of uterine sex steroid receptors by ovarian hormones and effects of estradiol on gonadotropin secretion and follicular growth /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2001. http://epsilon.slu.se/avh/2001/91-576-5915-X.pdf.

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33

Claes, Anthony N. J. "ANTI-MÜLLERIAN HORMONE IN STALLIONS AND MARES: PHYSIOLOGICAL VARIATIONS, CLINICAL APPLICATIONS, AND MOLECULAR ASPECTS." UKnowledge, 2014. http://uknowledge.uky.edu/gluck_etds/18.

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Anti-Müllerian hormone (AMH) is a homodimeric glycoprotein that is best known for its role in regression of the Müllerian duct in the male fetus. Accumulating evidence indicates that AMH also has an important role during different physiological processes after birth. In contrast to other species, relatively little is known about AMH in the horse. In chapter one, developmental and seasonal changes in serum AMH concentrations in male horses were determined, and the use of AMH for determination of retained cryptorchid testes was established. In chapter two, the interrelationship between plasma AMH concentrations, antral follicle counts (AFC), and age in mares was evaluated. Molecular and hormonal changes in the equine follicle with regard to variations in antral follicle count and follicular development were examined in chapter three. In chapter four, the effect of AFC on age-related changes in follicular parameters in light-type horse mares was examined. Peripheral AMH concentrations were significantly higher in prepubertal colts than in postpubertal stallions and varied with season in mature stallions with higher concentrations during the physiological breeding season. Furthermore, serum AMH concentrations were significantly higher in cryptorchid stallions compared to intact stallions or geldings. Circulating AMH concentrations varied widely amongst mares of the same age while the repeatability of AMH was high within and between estrous cycles. More importantly, AMH concentrations were positively associated with AFC, and this relationship increased with mare age. In addition, variations in AMH concentrations or AFC were associated with molecular differences in granulosa cells of growing follicles, and the expression of AMH and genes co-expressed with AMH in the equine follicle as well as intrafollicular AMH concentrations decreased during follicular development. Finally, the inter-ovulatory interval and length of the follicular phase is increased in aged mares with low AFC. In conclusion, AMH is a useful biomarker for cryptorchidism in stallions and ovarian reserve in mares. Furthermore, follicular function was interrelated to AFC or AMH based upon molecular differences in growing follicles, while age-related changes in follicular parameters are linked to differences in AFC.
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34

Dalle, Luche Greta. "Validation and use of a HPLC-MS/MS method for the analysis of multiple steroid hormones in humpback whale blubber." Thesis, Griffith University, 2020. http://hdl.handle.net/10072/392397.

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This thesis describes the novel use of multiple steroid hormone analysis to investigate and gain understanding of previously unknown aspects of the endocrinology and reproductive biology of the Southern Hemisphere humpback whale (Megaptera novaeangliae). Steroid hormones are a class of structurally related molecules that function as messengers in a variety of important physiological processes (e.g. salt homeostasis, immune system, sexual development and reproductive cycles). A number of endogenous steroid hormones have been identified as critical for reproduction (e.g. androgens, progestogens, oestrogens) and stress response (e.g. corticosteroids) in mammals. Understanding the species-specific roles and baseline levels of endogenous steroid hormones enable these compounds to be used as biomarkers of reproductive status and stress exposure. The use of steroid biomarkers for these purposes promises to be extremely advantageous in cetacean species, since other approaches often require increased time and resources. However, the collection and interpretation of steroid hormone data in the humpback whale is currently limited by methodological issues (e.g. challenging sampling, difficult comparison between sample types, analytical approach restricted to single hormone analysis), and by a general lack of detailed knowledge of the humpback whale endocrine system. Collection of biological samples from cetaceans is inherently difficult. In particular, free-swimming individuals of baleen whale species, including humpback whales, cannot be kept in captivity, nor they can be immobilised for sampling. Contemporary studies have demonstrated that steroid hormones analysis is viable in baleen species through the use of remotely collected tissues and fluids (i.e. faeces, blow, blubber). The seasonal migration of the humpback whales from the Antarctic feeding areas to the tropical breeding grounds, however, imposes further restrictions in regard to sample types and timing of collection. To date, blubber is the only matrix employed for steroid analysis in this specie and comprehensive seasonal steroid hormone changes have not being studied. Blubber is a lipid-rich tissue, able to sequester traces of steroid hormones from circulation. This is advantageous as multiple types of steroid hormones are likely to be present in this tissue. However, steroid hormones in blubber, particularly those at trace levels, can only be quantified by using sensitive techniques that need to accommodate the presence of lipids in the matrix. Enzyme immunoassay (EIA) is typically used for steroid hormone analysis in complex matrices, as it requires minimal sample preparation. Although EIA provides high sensitivity, its precision can suffer due to the indirect nature of the measurements and by the possibility of cross-reactivity. A significant disadvantage of employing EIAs for the investigation of species-specific endocrinology is that each EIA quantifies only a single steroid hormone, or a single class of steroid metabolites in its ensemble. Single steroid hormone measurements can be misleading, as steroid hormones act in concert. The same steroid hormone can have different roles and increase or decrease in concentration to accommodate different biosynthetic pathways (e.g. acting as an active metabolite, or as a precursor to or degradation product from other steroids). Liquid chromatography coupled with tandem mass-spectrometry (LC-MS/MS) represents an alternative to EIAs, as it can provide accurate and precise quantification of multiple steroid hormones from the same sample portion. Major issues in LC-MS/MS methods include the coelution of multiple analytes or the interference of matrix components, which can sometimes be resolved only through a trade-off between analyte resolution and sensitivity. These challenges can however be identified prior to the analysis, and overcome, at least partially, by optimising the sample extraction and cleanup. This thesis aimed to adapt and validate a LC-MS/MS method for extracts of humpback whale blubber, and to evaluate use of multiple steroid hormone measurements in relation to reproductive status and possible stress exposure from free-ranging individuals. Blubber samples from stranded humpback whale carcasses were initially employed to assess the applicability, scope, and repeatability of a LC-MS/MS method for the analysis of multiple steroid hormones (Chapter 2). The method, initially developed for bottlenose dolphin (Tursiops truncatus) blubber, proved to be applicable to the comparatively lipid-rich humpback whale outer blubber. Levels of five corticosteroids and six reproductive steroids (including androgens, progestagens and oestrogens) were determined in humpback whale blubber, and ten of these analytes could be quantified with high accuracy (error on amended samples < 15%) and repeatability (percent standard deviation < 15%). The multi-steroid hormone profiles obtained by the stranded carcasses were also investigated as potentially indicative of the endocrinological responses of some of the whales to stress exposure. Subsequently, the LC-MS/MS method was applied to biopsy extracts from freeswimming humpback whales collected at two time points of the whale breeding season over multiple years. The application of this methodology to live biopsies resulted in a smaller number of analytes detected, predominantly as an effect of the corticosteroid analytes being lower in concentration or undetectable in these samples. The quantified steroid hormones provided, however, novel insights into endocrinology and reproductive biology of female (Chapter 3) and male (Chapter 4) humpback whales. In Chapter 3, we show how the use of a previously validated pregnancy concentration threshold for the single hormone progesterone failed to detect any pregnant females based on LC-MS/MS analysis of blubber extracts from 23 females sampled while approaching the breeding grounds. However, by considering multiple steroid profiles including androgens and cortisol, we suggest that relatively high blubber concentrations of androstenedione may distinguish pregnant individuals during the last month of gestation. This hypothesis is supported by reference to steroid hormone measurements through pregnancy in evolutionarily related mammal species, although further work (e.g combining photo identification) is required to provide conclusive evidence. In addition, the same previously validated progesterone threshold resulted in an unexpectedly low proportion of pregnant females (3%) from among 29 females departing the breeding grounds. This prompted the suggestion of a new lower progesterone concentration threshold for assignment of early pregnancy status. In Chapter 4, the seasonal variations in blubber steroid hormone concentration in males are examined through the breeding season. Lowering of testosterone during the expected peak in reproductive activity suggests asynchronicity between blubber testosterone levels and male fertility. Correlation analyses among multiple hormone couples are used to postulate the changes in biosynthetic pathways behind the large interseasonal variations in steroid concentrations. These large intra-season variations in blubber androgens and a contrasting relationship with cortisol across the migration, encourages further investigation on the effects of age and sexual maturity on concentrations of these two hormones. This is necessary before they can be used as biomarkers for reproductive status or stress exposure. An application of how some of the multi-hormone information can be used to improve humpback whale monitoring is provided in Chapter 5. Early and late pregnancy diagnoses as formulated in Chapter 3, are combined with body condition information simultaneously measured in the same female individuals. Superior body condition among late-pregnant female corroborated previous observations that females would increase their feeding opportunities before parturition in order to support, as capital breeders, the combined energetic cost of migration and lactation. In contrast, no relationship was found between whales identified as early pregnant and their body condition compared to the rest of the migrating females. These results suggest that body condition and fertility might not be directly related during the breeding season. Instead, annual winter-feeding efficiency might be more important than accumulated energy stores in guaranteeing the annual reproductive success in females of this species. Overall, by analysing for a larger suite of steroid compounds and focusing on a comparatively less studied period of the migration, this work revealed some limitations of the current methodology used to measure steroid hormones in humpback whales. These findings enhance our knowledge of the humpback whale endocrine system and provide new approaches for the diagnostic use of steroid hormones profiles in free-swimming humpback whales.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
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35

Johnson, Justin M. "Characterization of the Immune Response to Anti-Müllerian Hormone." Cleveland State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=csu1606840042907281.

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36

Ligocki, Isaac Young. "Expanding Scales of Influence: Behavioral, Physiological, and Reproductive Implications of Relative Power within Social Groups." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1428601259.

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37

Crossin, Glenn Terrence. "Factors affecting the timing and success of sockeye salmon spawning migrations." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/995.

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Migration timing is a conserved life-history trait. To address the hypothesis that reproductive hormones are principal determinants of migration timing, I physiologically biopsied over 1000 sockeye salmon and monitored their subsequent behaviour with acoustic and radio telemetry as they migrated from the Pacific Ocean toward and into the Fraser River, and then onward to distant spawning areas. Links between physiology, behaviour, and survival were examined. Circulating testosterone was found to be positively correlated with the rates of river entry in Late-run females but not in males, despite having concentrations that were equal if not higher than those of females. The notion of protandrous migration, in which males synchronize their activities to the reproductive and migratory schedules of females, was postulated as the basis for this difference. Once in river however, successful males and females were those that (1) took longest to enter the river, and (2) had high somatic energy, low testosterone, and low gill Na+,K+-ATPase activities. An experimental test of the effect of reproductive hormones on the regulation of migration timing proved inconclusive. Relative to controls, GnRH and (or) testosterone treatment did not influence rates of ocean travel by males. Unfortunately, no females were examined. Nevertheless, significant, positive correlations between initial testosterone and travel times were found irrespective of hormonal treatment, which was unexpected but consistent with the previous studies. In an experimental simulation of an ‘early’ migration, normally timed Late-run sockeye exposed to typical 10 ºC river temperatures and then released to complete migration were 68% successful. In contrast, salmon held at 18 °C and released were half as successful. The expression of a kidney parasite was near maximal in the 18 °C fish and undetectable in the 10 °C fish. Only gill Na+,K+-ATPase activity differed between groups, with a drop in the 18 °C fish. Though no clear stress, reproductive, or energetic differences were observed between groups, the ultimate effect of high temperature treatment was high disease expression, slowed migration speeds, and high migration mortality. Changes in reproductive schedules, due to changes in latitudinal ocean distributions, are discussed as potential causes of early migration by Late-run sockeye.
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38

Marsh, Wendy K. "Clinical Course of Bipolar Disorder During the Menopausal Transition: Comparison with Reproductive Age and Post Menopausal Women: A Master's Thesis." eScholarship@UMMS, 2010. https://escholarship.umassmed.edu/gsbs_diss/517.

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Introduction: The late menopausal transition is a time of increased risk of depression in the general population. Nonetheless, mood course during the late menopausal transition in women with bipolar disorder in relatively unknown. Methods: Mood state data in 519 reproductive age women (5989 clinic visits), 116 late menopausal transition (perimenopausal) women (2046 visits), and 133 postmenopausal women (1,437 visits) with bipolar disorder who were receiving optimized naturalistic treatment in the multisite STEP-BD study over an average of 19.8±15.5 months were analyzed for proportion of clinic visits with syndromal depression, mood elevation and euthymia between the three groups. History of postpartum and perimenstrual mood exacerbation as well as hormone therapy use were evaluated as potential predictors of mood. Results: No significant difference in the proportion of clinic visits with syndromal depression was found between reproductive age (18.1%), perimenopausal (18.1%) and postmenopausal (19.3%) women. Reproductive age women had significantly greater proportion of visits with syndromal mood elevation (5.3%) compared to perimenopausal (4.1%, Z=2.1, p2(3, N = 9960) = 19.8, p Conclusions: While proportion of clinic visits with syndromal depression did not differ among the three reproductive groups, thirteen women who had recorded transition from perimenopause to postmenopause showed significantly greater depression than reproductive age, perimenopausal or postmenopausal women. Proportion of visits with euthymia or with syndromal mood elevation decreased from reproductive age to perimenopausal to postmenopausal women. Reported history of mood exacerbation during times of hormonal fluctuation, or current use of hormone therapy, was not significantly associated with depression during the perimenopause. Limitations include women excluded due to absence of menstrual data. Future studies should include hormonal assessments.
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Rojas-Rodriguez, Raziel. "Adaptations of Adipose Tissue Expandability in Gestation are Associated with Maternal Glucose Metabolism." eScholarship@UMMS, 2019. https://escholarship.umassmed.edu/gsbs_diss/1048.

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Pregnancy induces maternal metabolic adaptations including mild glucose intolerance and weight gain in order to support fetal development and lactation. Adipose tissue (AT) function in gestation is featured by reduced insulin sensitivity and fat mass accrual which partly accounts for the weight gain in pregnant women and adaptation of glucose metabolism. A common metabolic pregnancy complication is gestational diabetes mellitus (GDM), a disease characterized by impaired glucose tolerance with onset in gestation. However, the relationship between AT expandability and glucose metabolism in gestation is not well understood. The goal of this thesis was to investigate the adaptations of human AT expansion induced by pregnancy, how these changes are reflected in pregnancies complicated with GDM and characterize a mouse model to study the mechanisms underlying this disease. This dissertation illustrates that pregnancy promotes AT expandability by a signaling mechanism between placental pregnancy-associated plasma protein-A (PAPP-A) and AT- insulin-like growth factor binding protein-5 (IGFBP5). In addition, gravidas with GDM showed impaired AT expansion. Studies investigating the relationship between PAPP-A and glycemic state demonstrated that low levels of PAPP-A in the 1sttrimester are highly associated with the development of GDM. Moreover, PAPP-A knockout mice exhibit reduced insulin sensitivity and impaired AT growth exclusively in gestation. These results expand the knowledge of AT biology in gestation and have the potential to improve maternal care by proposing PAPP-A as an early biomarker and possible therapeutic for GDM. It also introduces a new mouse model to study the etiology of gestational diabetes.
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40

Brodin, Thomas. "Ovarian Reserve and Assisted Reproduction." Doctoral thesis, Uppsala universitet, Obstetrik & gynekologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-192998.

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Treatment success in IVF-ICSI is mainly limited by female age, but differences in ovarian reserve (OR; the remaining pool of oocytes and their quality) between individuals modify treatment prerequisites among women of similar age. OR may be assessed by OR tests (ORTs). The main aims of this work were to study menstrual cycle length (MCL), basal levels of circulating gonadotrophins, antral follicle count (AFC) and serum Anti-Müllerian hormone (AMH) levels and their associations with and prognostic capacities regarding IVF-ICSI outcome in large cohorts of unselected women. Age-adjusted MCL was positively and linearly associated with pregnancy rates (PRs), live-birth rates (LBRs) and ovarian response to controlled ovarian hyperstimulation. An MCL of >34 days almost doubled the LBR compared with an MCL of <26 days. The grouped variable ‘combined FSH and LH levels’ was superior to both individual gonadotrophin levels and the LH:FSH ratio. The highest mean PR was seen in connection with a combination of FSH <6.7 U/l with LH >4.9 U/l; PRs were lowest when FSH-LH levels were opposite to this (high-low) and intermediate when FSH-LH levels were low-low or high-high. Associations with LBR and ovarian response were similar as those for PR. AFCs and serum AMH levels were positively and log-linearly associated with PR, LBR and ovarian response. Success rates levelled out above AFC 30 or AMH 5 ng/ml. Treatment outcome was superior among women with polycystic ovaries. Among the studied ORTs, logAFC and logAMH concentration correlated most strongly. After multivariate testing, entering all studied ORTs, AMH and female age remained independently associated with LBR. AMH + AFC + age predicted both poor and excessive ovarian responses with high accuracy. Adjusting for age and oocyte yield, all ORTs remained significant for LBR, implying that ORTs also capture information on oocyte quality. In conclusion, measures of OR are strongly associated with PR, LBR and ovarian response in a log-linear fashion, and partly reflect oocyte quality. The OR spectrum is continuous, from small ‘oligofollicular’ ovaries (the low extreme) to polycystic ovaries (the high extreme). Among the studied ORTs, AMH together with age provide the most powerful basal estimate for IVF/ICSI outcome.
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41

Drolet, Renée. "Endocrinologie reproductive et métabolique chez la femme." Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27637/27637.pdf.

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42

Kugelmeier, Tatiana. "Avaliação endocrinológica do ciclo ovariano de macaco bugio (Alouatta caraya - HUMBOLDT, 1812) por meio de extração e dosagem de metabólitos de esteróides fecais." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/10/10131/tde-19042007-142326/.

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A endocrinologia ovariana de cinco fêmeas de bugio da espécie Alouatta caraya foi estudada por meio de extração e dosagem de metabólitos fecais de estrógenos e progestinas durante um período de cinco meses. Adicionalmente observou-se a presença de eritrócitos por meio de citologia vaginal em três das fêmeas estudadas. Duas fêmeas, uma em condição nutricional desfavorável e outra pré-púbere, apresentaram concentrações basais de estrógenos com mediana menor que 3,7 ng/g e de progestinas menor que 29,7 ng/g de fezes úmidas. Nas outras três fêmeas a mediana dos valores de pico de estrógenos fecais foi 711,55 ng/g e dos valores basais 130,51 ng/g de fezes úmidas. Para as progestinas fecais a mediana dos valores de pico foi 2653,54 ng/g e dos valores basais foi 149,88 ng/g de fezes úmidas. Nestes três animais as concentrações de ambos os metabólitos apresentaram uma variação cíclica e o intervalo entre picos de estrógenos fecais foi 19,6±1,9 dias (média±EPM). Estes metabólitos permaneceram elevados durante 9,1±0,9 dias. Elevações sustentadas de metabólitos fecais de progestinas acompanhadas de pico e elevações de metabólitos fecais de estrógenos foram observadas em apenas quatro períodos. Nestes casos ambos os metabólitos elevaram-se aproximadamente ao mesmo tempo e estimou-se que a ovulação tivesse ocorrido antes do início destas elevações. Os períodos de sangramento coincidiram com a queda nas concentrações de estrógenos e progestinas fecais.
The ovarian endocrinology was assessed in five female howler monkeys (Alouatta caraya) by means of estrogen and progestogen metabolites extracted from fecal samples. Measurements were conducted for a period of five months, and erythrocytes were observed by vaginal cytology, in three females. In one subadult and in one undernourished female, estrogen concentrations remained at median basal levels <3.7ng/g, and the progestogen concentrations were <29.7ng/g of wet feces for almost the entire period of the experiment. For the other three females, median fecal estrogen peak concentration was 711.55ng/g and basal concentration was 130.51ng/g of wet feces. Median fecal progestogen concentration was 2653.54ng/g and for basal concentration was 149.88 ng/g of wet feces. The three females were found with a cyclical pattern for both metabolites concentrations, with fecal estrogen peak intervals of 19.6±1.9 (mean±SEM) days and the estrogen metabolites remained elevated for 9.1±0.9 days. Fecal progestogen showed sustained elevations concurrently with fecal estrogen increase only in four periods and it was presumed that ovulation had occurred before the onset of those elevations. Bleeding periods occurred with the falling of both steroid metabolites.
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43

Miranda, Robert Alan. "Effects of exposure to environmental pollutants on sexual behavior, reproduction, and brain gene expression." Thesis, Northern Arizona University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3562152.

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Environmental pollutants can act as endocrine disruptors to affect the biology of organisms including, development, reproduction, behavior, and overall health. Many endocrine disrupting chemicals (EDCs) can mimic or inhibit functions of sex steroids which are critical for the development and maintenance of vertebrate reproductive systems. Sex steroids also interact with arginine vasotocin (AVT)/arginine vasopressin (AVP; mammalian homologue) systems to mediate vertebrate social and sexual behaviors, including vocalizations in male anurans. I used the Western clawed frog, Xenopus tropicalis, as an amphibian model species to evaluate the effects of exposure to EDCs on AVT-regulated behaviors and on brain AVT and sex steroid signaling systems.

In order to understand the role of neurohormones and social stimuli in behavior of X. tropicalis, I studied the effect AVT and human chorionic gonadotropin (hCG) administration and the influence of different social contexts on sexual behaviors, including calling, in males. I found that AVT and hCG treatment alone and in combination induces male sexual behavior, and the presence of a female is necessary to stimulate this behavior. I also analyzed the expression of genes related to AVT and sex steroid signaling in the brain of male and female X. tropicalis to identify genes that are expressed sexually dimorphically and could be potentially altered by EDC exposure.

Then I utilized the behavior and gene expression assays I developed to study the effects of developmental exposure to the synthetic androgen 17β-trenbolone (17β-TB) on behavior, fecundity, morphology, and brain gene expression in adult X. tropicalis. Developmental 17β-TB exposure reduced sexual behavior and inhibited female egg release during breeding trials. Exposure to 17β-TB also blocked oviduct development and altered AVT-related brain gene expression in females.

In another study I evaluated the effects of adult exposure to the common EDCs bisphenol A (BPA), nonylphenol (NP), and triclosan (TCS) or a mixture of the three on sexual behavior, morphology, and brain gene expression in adult male Xenopus tropicalis. Behavior and brain gene expression were not significantly affected, but TCS-exposed animals had a lower normalized liver weight than animals exposed to BPA or the chemical mixture. Males exposed to BPA, NP, and the mixture also exhibited increased oviduct development compared to TCS-exposed males, and the source of the animals influenced oviduct development.

Results from my dissertation research demonstrate that exposure to endocrine disruptors can affect multiple levels of physiology. Gender, timing of exposure and nature of the chemical are also critical factors in determining these physiological effects. Importantly, because there is evolutionary conservation in vertebrates for the role of sex hormones in regulating the reproductive system as well as the AVT/AVP system and related social behaviors, my work has important broader implications for endocrine-disrupting effects from environmental chemical exposure for all wildlife and humans.

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44

Jordan, Katherine Mead. "Characterization of seasonal reproduction in Virginia Tech Selection Line, St. Croix, and Suffolk ewes." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/28663.

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This dissertation research contained three studies. The first two studies were conducted to investigate the ability of ewes to rebreed while lactating during seasonal anestrus. Breeds studied included the Virginia Tech Out-of-season (OOS) Line, which is a wool line genetically selected to lamb in the fall, and the St. Croix, a hair breed of tropical origin thought to be lowly seasonal. When January-lambing ewes were exposed to rams while lactating in April, significantly more OOS than St. Croix ewes were marked by rams in the first 21 d and total 39 d of ram exposure (58.3 vs. 8.7%, P = 0.0003 and 95.8 vs. 43.5%, P < 0.0001). Percentages of ewes diagnosed pregnant (53.2%) and percentages of ewes lambing (41.3%) were not different between breeds. When March-lambing OOS ewes were exposed to rams while lactating in May, 52.9% of ewes were marked though only 20% of ewes exposed to rams gave birth to viable lambs. Both OOS and St. Croix ewes appear to be well suited to accelerated production systems involving 7 to 8 mo lambing intervals. However, reduction of lambing intervals to 6 to 7 mo appeared to have detrimental effects on fetal survival in OOS ewes. In a third study, alterations in endocrine profiles associated with differing degrees of hypothalamic sensitivity to estradiol-negative feedback and changing daylength in OOS, St. Croix, and Suffolk ewes in the absence of rams were investigated for 1 yr. The results show for the first time that based on progesterone profiles from intact ewes, St. Croix ewes do not have shorter anestrous periods than ewes of wool breeds, as previously thought. Based on luteinizing hormone profiles from ovariectomized ewes treated with estradiol implants, the duration of luteinizing hormone inhibition was shorter in OOS than Suffolk ewes (68 vs. 170.2 d, P = 0.02), but was not different from that found in St. Croix ewes (124.8 d). Specific roles for thyroxine and prolactin in timing the breeding season could not be assigned. This study was the first known use of the ovariectomized, estradiol-implanted ewe model to compare degree of reproductive seasonality in different breeds.
Ph. D.
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45

Greives, Timothy J. "The role of kisspeptin in the regulation of seasonal reproduction in Siberian hamsters (Phodopus sungorus)." [Bloomington, Ind.] : Indiana University, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3378351.

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Thesis (Ph.D.)--Indiana University, Dept. of Biology, 2009.
Title from PDF t.p. (viewed on Jul 8, 2010). Source: Dissertation Abstracts International, Volume: 70-10, Section: B, page: 5920. Adviser: Gregory E. Demas.
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46

Baran, Nathalie. "Prolactine & reproduction : recherche de gènes régulés par la prolactine pendant la gestation en utilisant le modèle de souris déficiente en récepteur de la prolactine." Paris, Muséum national d'histoire naturelle, 2002. http://www.theses.fr/2002MNHN0001.

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La prolactine (PRL) joue un rôle clef dans les fonctions de la reproduction. Les souris déficientes en récepteur de la PRL (RPRL-/-) sont stériles en partie à cause d'une altération de la synthèse des stéroi͏̈des essentiels à la gestation. Toutefois, l'administration de progestérone (P4) chez ces souris restaure l'implantation mais ne suffit pas à maintenir la gestation à terme. Nous avons recherché dans l'utérus des gènes cibles de la PRL impliqués dans les processus implantatoires grâce à une technique de biologie moléculaire, le mRNA Differential Display. Nous avons isolé 45 clones-148, réprimés pour la plupart en présence de signal PRL. L'ensemble de ces clones ont été identifiés mais seuls deux ont été étudiés : Le transcrit UA-3, homologue à la protéine neuronale P311, est régulée par la prolactine et les stéroi͏̈des pendant la gestation dans l'ovaire et l'utérus. UA-3 est fortement exprimé dans les sites d'implantation des embryons aux stades précoces de la gestation. UA-3 est impliqué dans les phénomènes prolifératifs et invasifs lors du remodelage utérin. Le transcrit UA-3 est localisé dans les tissus prolifératifs, l'embryon, la decidua ou les cellules de la granulosa ; Le transcrit UA+4, homologue à la décysine, est une métalloprotéase de la famille ADAM. UA+4 est régulé par la PRL et les stéroi͏̈des dans l'utérus et l'ovaire. Le transcrit UA+4 est co-localisé dans les mêmes types cellulaires que le RPRL au jour 5. 5 de gestation. Il est aussi expŕimé dans le spongiotrophoblaste à mi-gestation. Sa régulation coi͏̈ncide avec l'augmentation de la perméabilité vasculaire lors du remodelage de la décidua et l'angiogenèse nécessaire au bon déroulement de la gestation.
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47

Dimastrogiovanni, Giorgio. "Responses to environmental xenobiotics: from endocrine disruption to lipid homeostasis imbalance." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/328711.

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Many chemicals are continuously entering into the aquatic environment, as a result of their widespread use, disposal and accidental release. Several of these xenobiotics may disrupt reproductive functions of both vertebrates and invertebrates by adversely affecting endocrine signaling pathways, and may also lead to weight gain and metabolic disorders by altering critical pathways involved in lipid homeostasis and metabolism. However, knowledge about the effects of potential endocrine and lipid disrupters, together with information about their metabolism and elimination, in aquatic organisms is still limited. In this context, the present thesis investigated: the metabolism of the synthetic polycyclic musk HHCB and potential effects on the androgen production in the European sea bass (Dicentrarchus labrax); the enzymatic pathways involved in the metabolism of the steroid precursor progesterone (P4) in a model invertebrate species, Mytilus galloprovincialis; and the use of different liver cell lines (RTL-W1 and ZFL) as in-vitro models to assess the ability of known endocrine disrupters (i.e. TBT, TPT, 4-NP, BPA, and DEHP) to disrupt lipid homeostasis in fish cells. We found that HHCB is actively metabolized into a hydroxylated metabolite by sea bass, suggesting the determination of HHCB and/or its hydroxylated metabolite in bile as a tool to assess environmental exposure in wild fish. Furthermore, HHCB inhibited CYP17 and CYP11β catalyzed activities in-vivo, showing the potential to alter to some extent the synthesis of androgens in fish. Then, it was shown the ability of mussels to actively metabolize P4 to 5-alpha-DHP and 3-beta,20-one, with no evidence for the synthesis of 17-aplha-hydroxyprogesterone or androstenedione. Moreover, exposure to high concentrations of P4 (10 micrograms/L) accelerated gamete maturation and release, but had no significant effect on steroid levels or steroid metabolizing enzymes. Thus, environmental concentrations of P4, detected in the ng/L range, are unlikely to have an endocrine action in mussels. The selected endocrine disrupters altered the expression of genes related to lipid metabolism in RTL-W1 cells and produced significant changes in membrane lipids and TAGs. BPA and DEHP significantly induced the intracellular accumulation of TAGs, the effect being more evident after shorter exposure times, while all the compounds tested apart from TPT induced significant changes in membrane lipids –PCs and PC-plasmalogens─, indicating a strong interaction of the toxicants with cell membranes, and possibly with cell signaling. The mode of action of these chemicals is multiple and complex and no clear association between expression of lipid related genes and TAG accumulation was detected in RTL-W1 cells. On the other hand, TBT modified the intracellular lipid profile of ZFL cells but induced triglyceride accumulation only when the culture medium was supplemented with lipids. Finally, being the liver the main site for ‘de novo’ synthesis of lipids, the use of these fish cell lines (i.e. RTL-W1 and ZFL) can be a valuable in-vitro tool to estimate the potential of different compounds and their mixtures to interfere with lipid metabolism in hepatocytes under different exposure conditions (viz. supplementation of cell medium with specific lipids to emulate a lipid reach diet, different exposure lengths and concentrations).
El ambiente acuático es especialmente susceptible a la contaminación, ya que los compuestos químicos pueden llegar a los ríos, lagos y mares, por diferentes vias. Estos xenobióticos pueden afectar las funciones reproductoras, y también perjudicar vías clave involucradas en la adipogénesis y el metabolismo lipídico. Entonces, la necesidad de investigar los efectos de posibles disruptores endocrinos (EDs) y/o lipídicos sobre la fáuna acuática es evidente. El objetivo de esta tesis ha sido evaluar los efectos de estos contaminantes ambientales sobre organismos acuáticos no diana, investigando: el metabolismo y mecanismo de acción del galaxolide (HHCB) en lubinas; posibles alteraciones del sistema endocrino de mejillones expuestos a progesterona (P4) y las vías enzimáticas involucradas en su metabolismo; y la utilización de dos líneas celulares (RTL-W1 y ZFL) para evaluar la capacidad de disruptores endocrinos (TBT, TPT, 4-NP, BPA, y DEHP) de modificar la homeostasis lipídica celular. De este modo, se vio que HHCB puede ser metabolizado por la lubina y que actúa como un inhibidor débil de las actividades CYP17 y CYP11β, pudiendo perjudicar la biosíntesis de esteroides relacionados con la función testicular. Luego, se describió la capacidad de mejillones de metabolizar P4, y el examen histológico de las gónadas mostró que la exposición a 10 μg/L de P4 inducía la maduración y liberación de gametos, aunque las concentraciones de P4 detectadas en el medio ambiente (ng/L) es poco probable que produzcan alteraciones a nivel endocrino en mejillones. En respecto a los efectos obesogenicos, se mostró la abilidad de los EDs estudiados de alterar la expresión de genes relacionados con el metabolismo lipídico en las células RTL-W1 y de causar cambios importantes en los lípidos celulares. Por otro lado, se evidenció la capacidad del TBT de alterar el perfil lipídico de las células ZFL y de inducir acumulación de triglicéridos en hepatocitos sólo cuando el medio de cultivo es suplementado con una mezcla lipídica. En general, la utilización de estas líneas celulares de hígado de pez, RTL-W1 y ZFL, puede ser un modelo in-vitro apto para evaluar la capacidad de contaminantes ambientales de interferir con el metabolismo lipídico en especies acuáticas.
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48

Chelini, Marie Odile Monier. "Efeito do estresse social sobre o comportamento materno do hamster Sírio (Mesocricetus auratus)." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/47/47132/tde-22032010-110353/.

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A flexibilidade da socialidade presente em muitas espécies sugere que muitos dos traços comportamentais e fisiológicos presentes em grupos sociais complexos possam existir em estado latente em indivíduos de espécies solitárias. Hierarquia de dominância e assimetria reprodutiva são traços característicos de espécies sociais. O hamster Sírio é um excelente modelo para o estudo do estresse social e dos seus efeitos fisiológicos e comportamentais. Na presente pesquisa foram enfocados os efeitos do alojamento em grupo antes e no início da gestação na fêmea de hamster Sírio. Investigou-se se o estresse social produz algum grau de assimetria reprodutiva nesta espécie solitária e se o sucesso reprodutivo e o comportamento materno das fêmeas variam em função do seu status social. Dois experimentos foram realizados envolvendo respectivamente 34 fêmeas de hamster criadas em grupo do desmame até o início do estudo e 76 fêmeas criadas isoladamente. Em cada experimento, um terço dos animais foram alojados em gaiolas individuais, enquanto pares de fêmeas desconhecidas umas das outras eram formados com os outros dois terços. O comportamento dos pares foi observado ao longo de 10 dias para determinar o status social de cada fêmea. Todas as fêmeas foram acasaladas neste período. Quatro dias após o parto, os filhotes foram contados, sexados e pesados e as ninhadas padronizadas a seis filhotes, três machos e três fêmeas. As mães e suas ninhadas foram observadas diariamente durante sessões de 40min e 13 categorias comportamentais foram registradas. No intuito de esclarecer os mecanismos fisiológicos subjacentes à relação entre estresse social e fertilidade, os níveis dos hormônios reprodutivos e dos glicocorticóides foram monitorados ao longo da gestação por métodos não-invasivos, previamente validados, de quantificação dos seus metabólitos nas fezes. Foi demonstrada, pela primeira vez, a adequação de um enzimaimunoensaio e de um conjunto diagnóstico comercial de radioimunoensaio para a quantificação respectiva dos metabólitos fecais de glicocorticóides em hamsters Sírios dos dois sexos e de testosterona no hamster Sírio macho, mas não da fêmea. As variações das concentrações de metabólitos fecais de progesterona, estrógenos e glicocorticóides, refletiram os perfis séricos descritos na literatura para hamsters gestantes. Os resultados mostram que quando fêmeas de hamster Sírio são alojadas individualmente após o desmame, sua fertilidade não é afetada pelo estresse social. Em contraste, quando as fêmeas são criadas em grupo, o estresse social tanto de isolamento como de subordinação a uma fêmea dominante induz um grau significante de assimetria reprodutiva, traço característico de espécies sociais que criam seus filhotes em comunidade. A manutenção de hamsters cativos adultos em grupos parece despertar traços comportamentais e fisiológicos presentes em grupos sociais complexos e que se encontram em estado latente nesta espécie solitária. A socialidade parece flexível no hamster e modulada pelas condições ecológicas.
The flexibility of sociality found in many species suggests that many of the behavioral and physiological mechanisms responsible for highly developed social interactions are present as latent traits, even in species usually considered as solitary. Social hierarchy and reproductive skew are typical features of social species. Syrian hamsters (Mesocricetus auratus) are an ideal model for the investigation of social stress and its physiological, neuroendocrine, and behavioral effects. The present research focused on the effects of group-housing prior to mating and on the first days of gestation of the female hamster. We investigated if social stress produces some degree of reproductive skew in this solitary species, and if female reproductive success varies as a function of social rank. Two experiments were carried out. The first one involved 34 females group-raised from weaning until the beginning of the trial and the second one 76 singly raised females. In each case one third of the animals were singly housed. Pairs of unrelative females were formed with the remaining animals. Pair behavior was observed through 10 days for assessment of the social rank of each female. All females were mated during this period. On day 4 post-partum, pups were counted, sexed, and weighed and litters were culled to six, three males and three females. Litters and dams were observed daily through 40-min sessions and 13 behavioral categories recorded. In order to assess the physiological relationship between social stress and fertility, we monitored reproductive hormones and glucocorticoids of solitary and pair-housed females during pregnancy by utilizing recently established non-invasive methods for measuring the respective hormone metabolites in the feces. The suitability of an enzyme immunoassay and of a commercial radioimmunoassay for respective quantification of fecal glucocorticoid metabolites of hamsters of both sexes and fecal testosterone metabolites in the male but not in the female was proven for the first time. The patterns of fecal progesterone, estrogen, and glucocorticoid metabolites were similar to blood profiles reported in the literature for pregnant hamsters. Our results showed that when female hamsters are singly housed from weaning, social stress did not affect their fertility. However, when females are group-raised, both isolation and subordination stress induced a significant reproductive skew, which is a characteristic feature of cooperative breeders. It seems that group-keeping of adult hamsters evokes social physiological and behavioral mechanisms present as latent traits in this solitary species. As in other rodents, sociability seems flexible in the Syrian hamster and our findings support the idea that social interactions may be a function of ecological conditions.
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49

Moore, Brittany Lynita. "The Effects of Intracerebroventricular Leptin on Milk Availability in Lactating Rats." Digital Commons @ East Tennessee State University, 2012. https://dc.etsu.edu/etd/1481.

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Abstract:
Reports have linked energy balance along with adipocyte derived leptin action to improved fertility. Recent evidence indicates that leptin hormone is present in breast milk and leptin receptors are well expressed in mammary epithelial cells. The hypothesis that insufficiency of leptin restraint in the hypothalamus may underlie infertility in rodents and the failure of lactating breast to express adequate amount of milk was tested. Female Sprague-Dawley rats were injected leptin through intracerebroventricular cannulation (ICVC) of the third ventricle. Female rats were mated with stud males and observed throughout gestation. Compared to the control groups, leptin treatment increased prolactin levels in the dams and increased milk transfer to pup. Hypothalamic mRNA leptin levels and brain size in the offspring from leptin treated dams were significantly higher than the control. These findings support the involvement of leptin in reproduction and could lead to better understanding of leptin transfer from dam to offspring.
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50

Kane, Erin Elizabeth. "Socioecology, stress, and reproduction among female Diana monkeys (Cercopithecus diana) in Cote d’Ivoire’s Tai National Park." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1503076541553319.

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