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1
Herrera-Ulloa, Angel, Jonathan Chacón-Guzmán, Gerando Zúñiga-Calero, Oscar Fajardo, and Ricardo Jiménez-Montealegre. "ACUICULTURA DE PARGO LA MANCHA LUTJANUS GUTTATUS (STEINDACHNER, 1869) EN COSTA RICA DENTRO DE UN ENFOQUE ECOSISTÉMICO." Revista Ciencias Marinas y Costeras 1 (December 21, 2009): 197. http://dx.doi.org/10.15359/revmar.1.11.
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La sobreexplotación pesquera y la búsqueda de alternativas ante la pobreza crónica han llevado a explorar el campo de la maricultura por medio de un enfoque ecosistémico se abrieron dos procesos paralelos: una estrategia e; investigación en laboratorio para el levantamiento larval de peces marinos tropicales y una estrategia de comanejo para desarrollar el cultivo de peces marinos tropicales. El pargo la mancha muestra gran potencial de producción de larvas y posterior cultivo en el mar. No mostró respuestas positivas a la inducción por medio de hormonas, el desarrollo de un ambiente adecuado para su reproducción espontánea, permitió tener desoves frecuentes y de calidad. La fase de levantamiento larval mostró contratiempos por el tamaño reducido de las larvas de pargo la mancha el manejo en tanques apropiados y el uso de enriquecedores permitieran mejorar los procesos y llegar a incrementar la producción de alevines. El enfoque ecosistémico permitió abrir los espacios necesarios que permitieron la operación de un proyecto piloto. La granja se creó con un enfoque productivo, pero también para turismo rural.Overfishing and the search for alternatives to it, led us to the explore mariculture as an option using an ecosystem-based approach through two parallel processes: an in-laboratory research strategy for larval rearing of tropical marine fish, and a strategy of co-management to develop tropical marine fish aquaculture. The spotted rose snapper shows great potential for larvae production and cage culture. This species showed no responses to hormone induction; however, the set up of a suitable environment allowed frequent, high-quality spontaneous spawnings. The larval rearing phase presented problems due to the small size of the larvae; although, management in appropriate tanks and the use of enrichments improved the processes, increasing the production of juveniles. This ecosystem approach allowed the operation of a profitable farm pilot project with a productive approach, but with rural tourism in mind as well.
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Boogert, Neeltje J., Robert F. Lachlan, Karen A. Spencer, Christopher N. Templeton, and Damien R. Farine. "Stress hormones, social associations and song learning in zebra finches." Philosophical Transactions of the Royal Society B: Biological Sciences 373, no. 1756 (August 13, 2018): 20170290. http://dx.doi.org/10.1098/rstb.2017.0290.
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The use of information provided by others is a common short-cut adopted to inform decision-making. However, instead of indiscriminately copying others, animals are often selective in what, when and whom they copy. How do they decide which ‘social learning strategy’ to use? Previous research indicates that stress hormone exposure in early life may be important: while juvenile zebra finches copied their parents' behaviour when solving novel foraging tasks, those exposed to elevated levels of corticosterone (CORT) during development copied only unrelated adults. Here, we tested whether this switch in social learning strategy generalizes to vocal learning. In zebra finches, juvenile males often copy their father's song; would CORT-treated juveniles in free-flying aviaries switch to copying songs of other males? We found that CORT-treated juveniles copied their father's song less accurately as compared to control juveniles. We hypothesized that this could be due to having weaker social foraging associations with their fathers, and found that sons that spent less time foraging with their fathers produced less similar songs. Our findings are in line with a novel hypothesis linking early-life stress and social learning: early-life CORT exposure may affect social learning indirectly as a result of the way it shapes social affiliations. This article is part of the theme issue ‘Causes and consequences of individual differences in cognitive abilities’.
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Meeran, Dawud, Henryk F. Urbanski, Susan J. Gregory, Julie Townsend, and Domingo J. Tortonese. "Developmental Changes in the Hormonal Identity of Gonadotroph Cells in the Rhesus Monkey Pituitary Gland." Journal of Clinical Endocrinology & Metabolism 88, no. 6 (June 1, 2003): 2934–42. http://dx.doi.org/10.1210/jc.2002-021001.
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To help elucidate the regulatory mechanism responsible for divergent gonadotrophin secretion during sexual maturation, we examined the gonadotroph population and hormonal identity of gonadotroph subtypes in pituitary glands of juvenile (age, 1.7 ± 0.2 yr) and adult (age, 12.3 ± 0.8 yr) male rhesus monkeys (Macacca mulatta). Serum LH and testosterone concentrations were, respectively, 3 and 7 times lower in juveniles than in adults, thus confirming the different stages of development. Immunohistochemistry revealed that the proportion of LH gonadotrophs in relation to the total pituitary cell population in the juvenile animals was significantly smaller than in the adults. In a subsequent study, double immunofluorescent labeling identified three distinct gonadotroph subtypes in both age groups: ones expressing either LH or FSH and another one expressing a combination of both gonadotrophins. Whereas the number of monohormonal LH cells per unit area was greater in the adults than in the juveniles, the number of monohormonal FSH gonadotrophs was remarkably lower. However, the proportion of FSH cells (whether mono- or bihormonal) within the gonadotroph population was similar between groups. Interestingly, the proportion and number of bihormonal gonadotrophs as well as the LH/FSH gonadotroph ratio were significantly greater in the adults than in the juveniles. Taken together, these data reveal that during the juvenile-adult transition period, not only does the pituitary gonadotroph population increase, but a large number of monohormonal FSH gonadotrophs are likely to become bihormonal. Because this morphological switch occurs when marked changes in plasma gonadotrophins are known to occur, it may represent an intrapituitary mechanism that differentially regulates gonadotrophin secretion during sexual development.
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Nunes, Scott, Eva-Maria Muecke, and Kay E. Holekamp. "Seasonal effects of food provisioning on body fat, insulin, and corticosterone in free-living juvenile Belding's ground squirrels (Spermophilus beldingi)." Canadian Journal of Zoology 80, no. 2 (February 1, 2002): 366–71. http://dx.doi.org/10.1139/z01-222.
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We evaluated the relationship between body fat and the metabolic hormones insulin and corticosterone in free-living juvenile Belding's ground squirrels (Spermophilus beldingi). Some free-living juveniles were provisioned with extra food high in fat and calories, and unprovisioned juveniles were used as controls. Body fat (as a percentage of body mass) of squirrels was regularly evaluated using non-invasive methods. Blood samples were also regularly collected from juveniles and assayed for plasma concentrations of insulin and corticosterone. Provisioned juveniles were fatter than unprovisioned juveniles during most of the active season, but differences in body fat disappeared near the end of summer as juveniles began fattening for hibernation. Thus, our data indicate that although body fat may fluctuate with energy availability early in the active season, it is regulated at precise levels as squirrels prepare for winter. Plasma corticosterone concentrations did not differ between provisioned and unprovisioned juveniles. However, plasma insulin concentrations were greater in provisioned than in unprovisioned juveniles early in the summer. Differences in insulin concentrations disappeared later in the active season, just prior to the disappearance of differences in body fat. Moreover, plasma insulin concentrations were significantly correlated with subsequent changes in body fat. Thus, our data suggest a link between insulin and seasonal regulation of body fat in juvenile S. beldingi.
5
PETER, F. "Juvenile thyrotoxicosis." Acta Endocrinologica 113, no. 4_Suppl (December 1986): S361—S366. http://dx.doi.org/10.1530/acta.0.112s361.
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ABSTRACT The incidence of juvenile thyrotoxicosis has not exceeded one case per 100,000 population per year in Hungary during the past decades. From more than 200 simultaneous determinations of serum thyroid hormones (T3, T4, FT4) it was concluded that increased FT4 concentrations are the most frequent findings in thyrotoxicosis, even when both or one of the other thyroid hormone concentrations (T3, T4) are normal,-TSH and prolactin responses to TRH were studied in 18 patients; TSH remained always undetectable whereas prolactin increased in half of the patients. A significant negative relationship was found between the prolactin response and the level of circulating thyroid hormone. Although the pituitary lactotrophin is controlled by thyroid hormones, thyrotrophin is more sensitive to thyroid hormone levels in juvenile thyrotoxicosis.-In 56 TRH tests during antithyroid drug therapy this test was not found to be useful in predicting the likelihood of long-term remission. - The low maintenance dose of antithyroid treatment (2.5-5.0 mg/day) without thyroid hormone addition seems to be a favourable mode of therapy in juvenile thyrotoxicosis.
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Chatrath, Ritu, Karen L. Ronningen, Peter LaBreche, Sandra R. Severson, Muthuvel Jayachandran, Margarita P. Bracamonte, and Virginia M. Miller. "Effect of puberty on coronary arteries from female pigs." Journal of Applied Physiology 95, no. 4 (October 2003): 1672–80. http://dx.doi.org/10.1152/japplphysiol.00099.2003.
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Vascular function changes following loss of ovarian hormones in women at menopause and in experimental animals following surgical ovariectomy. Little is known about changes in vascular function during hormonal transition from sexual immaturity (juvenile) to sexual maturity. Therefore, experiments were designed to determine effects of natural puberty on vascular function in female pigs. Tissue was studied from eight juvenile (2-3 mo) and eight adult (5-6 mo) female pigs. Plasma nitric oxide (NO) was measured, and mRNA for endothelium-derived NO synthase (eNOS) and eNOS protein were determined in aortic endothelial cells. Rings of coronary arteries were suspended for measurement of isometric force in organ chambers. Serum 17β-estradiol levels were comparable in the two groups, whereas the arithmetic mean of progesterone levels was about two-thirds lower in adults compared with juvenile pigs. Plasma NO was significantly higher in juveniles compared with adults, but mRNA and protein for eNOS were comparable. In coronary arteries, an α2-adrenergic agonist caused greater endothelium-dependent relaxations in rings from juvenile compared with adult pigs. Relaxations to bradykinin were similar in arteries from both groups, but inhibition of NO reduced relaxations only in arteries from juvenile pigs. Relaxations from NO were greater in arteries from adult compared with juvenile female pigs. In conclusion, coronary arterial endothelial and smooth muscle responses are selectively modulated at puberty in female pigs. At maturity, plasma NO is reduced and sensitivity of the smooth muscle to exogenous NO is increased. Posttranscriptional regulation of eNOS protein may explain differences in NO bioavailability in juvenile pigs.
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Tibbetts, Elizabeth A., Katherine Crocker, and Zachary Y. Huang. "Socially selected ornaments influence hormone titers of signalers and receivers." Proceedings of the National Academy of Sciences 113, no. 30 (July 8, 2016): 8478–83. http://dx.doi.org/10.1073/pnas.1602707113.
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Decades of behavioral endocrinology research have shown that hormones and behavior have a bidirectional relationship; hormones both influence and respond to social behavior. In contrast, hormones are often thought to have a unidirectional relationship with ornaments. Hormones influence ornament development, but little empirical work has tested how ornaments influence hormones throughout life. Here, we experimentally alter a visual signal of fighting ability in Polistes dominulus paper wasps and measure the behavioral and hormonal consequences of signal alteration in signalers and receivers. We find wasps that signal inaccurately high fighting ability receive more aggression than controls and receiving aggression reduces juvenile hormone (JH) titers. As a result, immediately after contests, inaccurate signalers have lower JH titers than controls. Ornaments also directly influence rival JH titers. Three hours after contests, wasps who interacted with rivals signaling high fighting ability have higher JH titers than wasps who interacted with rivals signaling low fighting ability. Therefore, ornaments influence hormone titers of both signalers and receivers. We demonstrate that relationships between hormones and ornaments are flexible and bidirectional rather than static and unidirectional. Dynamic relationships among ornaments, behavior, and physiology may be an important, but overlooked factor in the evolution of honest communication.
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Oi, Cintia Akemi, Helena Mendes Ferreira, Rafael Carvalho da Silva, Andreas Bienstman, Fabio Santos do Nascimento, and Tom Wenseleers. "Effects of juvenile hormone in fertility and fertility-signaling in workers of the common wasp Vespula vulgaris." PLOS ONE 16, no. 5 (May 17, 2021): e0250720. http://dx.doi.org/10.1371/journal.pone.0250720.
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In the highly eusocial wasp, Vespula vulgaris, queens produce honest signals to alert their subordinate workers of their fertility status, and therefore they are reproductively suppressed and help in the colony. The honesty of the queen signals is likely maintained due to hormonal regulation, which affects fertility and fertility cue expression. Here, we tested if hormonal pleiotropy could support the hypothesis that juvenile hormone controls fertility and fertility signaling in workers. In addition, we aimed to check oocyte size as a proxy of fertility. To do that, we treated V. vulgaris workers with synthetic versions of juvenile hormone (JH) analogue and a JH inhibitor, methoprene and precocene, respectively. We dissected the treated females to check ovary activation and analyzed their chemical profile. Our results showed that juvenile hormone has an influence on the abundance of fertility linked compounds produced by workers, and it also showed to increase oocyte size in workers. Our results corroborate the hypothesis that juvenile hormone controls fertility and fertility signaling in workers, whereby workers are unable to reproduce without alerting other colony members of their fertility. This provides supports the hypothesis that hormonal pleiotropy contributes to keeping the queen fertility signals honest.
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Siregar, Khoirotun Nisa, Fajar Maulana, Muhammad Zairin Jr., Alimuddin Alimuddin, and Widanarni Widanarni. "Controlling the cannibalism of African catfish juvenile by 17β‒estradiol hormone administration and the stocking density determination." Jurnal Akuakultur Indonesia 20, no. 1 (June 9, 2021): 72–81. http://dx.doi.org/10.19027/jai.20.1.72-81.
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An effort to increase the production of juvenile catfish is limited by the high mortality rate, especially caused by cannibalism. The hormonal treatment has been conducted as an effort to control cannibalism. This study used completely randomized factorial design, consisted of six treatments and three replications. There were two factors examined in this study, the first factor was different doses of 17β‒estradiol hormone (0, 30, and 60 mg estradiol‒17β/kg) incorporated in the feed, and the second factor was stocking density (150 and 300 fish/m2). Juvenile catfish with the size of 4.0 ± 0.1 cm were reared for 30 days in the 84 L aquarium. The results showed that hormone treatment could reduce cannibalism rate, type-I and II cannibalism compared to control (P<0.05). The results showed that the lowest of mortality was obtained in the treatment B (17β‒estradiol administration of 30 mg/kg, at stocking density of 150 fish/m2; P<0.05). The lowest cortisol level was found in treatment F, and the highest estradiol level was found in treatment F (17β‒estradiol administration of 60 mg/kg, at stocking density of 300 fish/m2; P<0.05). The lowest of blood glucose level was found in treatment B (P<0.05). The highest specific weight growth was found in the stocking density of 150 fish/m2 (P<0.05). The results of this study indicated that administration of 17β‒estradiol in feed could reduce the level of cannibalism in African catfish juvenile.
Keywords: cannibalism, Juvenile, catfish, estradiol‒17β, cortisol
ABSTRAK
Upaya untuk meningkatkan produksi benih ikan lele dibatasi oleh tingginya angka kematian, terutama yang disebabkan oleh kanibalisme. Pendekatan hormonal telah dilakukan sebagai upaya pengendalian kanibalisme. Penelitian ini menggunakan rancangan acak lengkap faktorial, terdiri dari enam perlakuan dan tiga ulangan. Ada dua faktor yang diteliti dalam penelitian ini, faktor pertama adalah dosis hormon 17β‒estradiol yang berbeda (0, 30, dan 60 mg/kg) yang diberikan melalui pakan, dan faktor kedua adalah padat tebar (150 dan 300 ekor/m2). Benih ikan lele berukuran 4.0 ± 0.1 cm dipelihara selama 30 hari di akuarium (84 L). Hasil penelitian menunjukkan bahwa perlakuan hormon dapat menurunkan tingkat kanibalisme tipe‒I dan II dibandingkan kontrol (P<0.05). Hasil penelitian menunjukkan bahwa mortalitas terendah diperoleh pada perlakuan B (pemberian 17β‒estradiol 30 mg/kg, pada padat tebar 150 ekor/m2; P<0.05). Kadar kortisol terendah ditemukan pada perlakuan F, dan kadar estradiol tertinggi ditemukan pada perlakuan F (pemberian 17β‒estradiol 60 mg/kg, pada padat tebar 300 ekor/m2; P<0.05). Kadar glukosa darah terendah ditemukan pada perlakuan B (P<0.05). Pertumbuhan bobot spesifik tertinggi ditemukan pada padat tebar 150 ekor/m2 (P<0.05). Hasil penelitian ini menunjukkan bahwa pemberian hormon 17β‒estradiol dengan dosis 30 mg/kg pakan, dan padat tebar 150 ekor/m2 dapat menurunkan tingkat kanibalisme pada benih ikan lele di Afrika.
Kata kunci: kanibalisme, juvenil, lele, 17β‒estradiol, kortisol
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Jindra, Marek. "Where did the pupa come from? The timing of juvenile hormone signalling supports homology between stages of hemimetabolous and holometabolous insects." Philosophical Transactions of the Royal Society B: Biological Sciences 374, no. 1783 (August 26, 2019): 20190064. http://dx.doi.org/10.1098/rstb.2019.0064.
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Insect metamorphosis boasts spectacular cases of postembryonic development when juveniles undergo massive morphogenesis before attaining the adult form and function; in moths or flies the larvae do not even remotely resemble their adult parents. A selective advantage of complete metamorphosis (holometaboly) is that within one species the two forms with different lifestyles can exploit diverse habitats. It was the environmental adaptation and specialization of larvae, primarily the delay and internalization of wing development, that eventually required an intermediate stage that we call a pupa. It is a long-held and parsimonious hypothesis that the holometabolous pupa evolved through modification of a final juvenile stage of an ancestor developing through incomplete metamorphosis (hemimetaboly). Alternative hypotheses see the pupa as an equivalent of all hemimetabolous moulting cycles (instars) collapsed into one, and consider any preceding holometabolous larval instars free-living embryos stalled in development. Discoveries on juvenile hormone signalling that controls metamorphosis grant new support to the former hypothesis deriving the pupa from a final pre-adult stage. The timing of expression of genes that repress and promote adult development downstream of hormonal signals supports homology between postembryonic stages of hemimetabolous and holometabolous insects. This article is part of the theme issue ‘The evolution of complete metamorphosis’.
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Segers, F. H. I. D., G. Berishvili, and B. Taborsky. "Egg size-dependent expression of growth hormone receptor accompanies compensatory growth in fish." Proceedings of the Royal Society B: Biological Sciences 279, no. 1728 (July 13, 2011): 592–600. http://dx.doi.org/10.1098/rspb.2011.1104.
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Large egg size usually boosts offspring survival, but mothers have to trade off egg size against egg number. Therefore, females often produce smaller eggs when environmental conditions for offspring are favourable, which is subsequently compensated for by accelerated juvenile growth. How this rapid growth is modulated on a molecular level is still unclear. As the somatotropic axis is a key regulator of early growth in vertebrates, we investigated the effect of egg size on three key genes belonging to this axis, at different ontogenetic stages in a mouthbrooding cichlid ( Simochromis pleurospilus ). The expression levels of one of them, the growth hormone receptor ( GHR ), were significantly higher in large than in small eggs, but remarkably, this pattern was reversed after hatching: young originating from small eggs had significantly higher GHR expression levels as yolk sac larvae and as juveniles. GHR expression in yolk sac larvae was positively correlated with juvenile growth rate and correspondingly fish originating from small eggs grew faster. This enabled them to catch up fully in size within eight weeks with conspecifics from larger eggs. This is the first evidence for a potential link between egg size, an important maternal effect, and offspring gene expression, which mediates an adaptive adjustment in a relevant hormonal axis.
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Oostra, Vicencio, Maaike A. de Jong, Brandon M. Invergo, Fanja Kesbeke, Franziska Wende, Paul M. Brakefield, and Bas J. Zwaan. "Translating environmental gradients into discontinuous reaction norms via hormone signalling in a polyphenic butterfly." Proceedings of the Royal Society B: Biological Sciences 278, no. 1706 (September 8, 2010): 789–97. http://dx.doi.org/10.1098/rspb.2010.1560.
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Polyphenisms—the expression of discrete phenotypic morphs in response to environmental variation—are examples of phenotypic plasticity that may potentially be adaptive in the face of predictable environmental heterogeneity. In the butterfly Bicyclus anynana , we examine the hormonal regulation of phenotypic plasticity that involves divergent developmental trajectories into distinct adult morphs for a suite of traits as an adaptation to contrasting seasonal environments. This polyphenism is induced by temperature during development and mediated by ecdysteroid hormones. We reared larvae at separate temperatures spanning the natural range of seasonal environments and measured reaction norms for ecdysteroids, juvenile hormones (JHs) and adult fitness traits. Timing of peak ecdysteroid, but not JH titres, showed a binary response to the linear temperature gradient. Several adult traits (e.g. relative abdomen mass) responded in a similar, dimorphic manner, while others (e.g. wing pattern) showed a linear response. This study demonstrates that hormone dynamics can translate a linear environmental gradient into a discrete signal and, thus, that polyphenic differences between adult morphs can already be programmed at the stage of hormone signalling during development. The range of phenotypic responses observed within the suite of traits indicates both shared regulation and independent, trait-specific sensitivity to the hormone signal.
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Qu, Zhe, William G. Bendena, Wenyan Nong, Kenneth W. Siggens, Fernando G. Noriega, Zhen-peng Kai, Yang-yang Zang, et al. "MicroRNAs regulate the sesquiterpenoid hormonal pathway in Drosophila and other arthropods." Proceedings of the Royal Society B: Biological Sciences 284, no. 1869 (December 13, 2017): 20171827. http://dx.doi.org/10.1098/rspb.2017.1827.
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Arthropods comprise the majority of all described animal species, and understanding their evolution is a central question in biology. Their developmental processes are under the precise control of distinct hormonal regulators, including the sesquiterpenoids juvenile hormone (JH) and methyl farnesoate. The control of the synthesis and mode of action of these hormones played important roles in the evolution of arthropods and their adaptation to diverse habitats. However, the precise roles of non-coding RNAs, such as microRNAs (miRNAs), controlling arthropod hormonal pathways are unknown. Here, we investigated the miRNA regulation of the expression of the juvenile hormone acid methyltransferase gene ( JHAMT ), which encodes a rate-determining sesquiterpenoid biosynthetic enzyme. Loss of function of the miRNA bantam in the fly Drosophila melanogaster increased JHAMT expression, while overexpression of the bantam repressed JHAMT expression and resulted in pupal lethality. The male genital organs of the pupae were malformed, and exogenous sesquiterpenoid application partially rescued the genital deformities. The role of the bantam in the regulation of sesquiterpenoid biosynthesis was validated by transcriptomic, qPCR and hormone titre (JHB3 and JH III) analyses. In addition, we found a conserved set of miRNAs that interacted with JHAMT , and the sesquiterpenoid receptor methoprene-tolerant ( Met ) in different arthropod lineages, including insects (fly, mosquito and beetle), crustaceans (water flea and shrimp), myriapod (centipede) and chelicerate (horseshoe crab). This suggests that these miRNAs might have conserved roles in the post-transcriptional regulation of genes in sesquiterpenoid pathways across the Panarthropoda. Some of the identified lineage-specific miRNAs are potential targets for the development of new strategies in aquaculture and agricultural pest control.
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Fontaine, Romain, Eirill Ager-Wick, Kjetil Hodne, and Finn-Arne Weltzien. "Plasticity in medaka gonadotropes via cell proliferation and phenotypic conversion." Journal of Endocrinology 245, no. 1 (April 2020): 21–37. http://dx.doi.org/10.1530/joe-19-0405.
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Follicle-stimulating hormone (Fsh) and luteinizing hormone (Lh) produced by the gonadotropes play a major role in control of reproduction. Contrary to mammals and birds, Lh and Fsh are mostly produced by two separate cell types in teleost. Here, we investigated gonadotrope plasticity, using transgenic lines of medaka (Oryzias latipes) where DsRed2 and hrGfpII are under the control of the fshb and lhb promotors respectively. We found that Fsh cells appear in the pituitary at 8 dpf, while Lh cells were previously shown to appear at 14 dpf. Similar to Lh cells, Fsh cells show hyperplasia from juvenile to adult stages. Hyperplasia is stimulated by estradiol. Both Fsh and Lh cells show hypertrophy during puberty with similar morphology. They also share similar behavior, using their cellular extensions to make networks. We observed bi-hormonal gonadotropes in juveniles and adults but not in larvae where only mono-hormonal cells are observed, suggesting the existence of phenotypic conversion between Fsh and Lh in later stages. This is demonstrated in cell culture, where some Fsh cells start to produce Lhβ, a phenomenon enhanced by gonadotropin-releasing hormone (Gnrh) stimulation. We have previously shown that medaka Fsh cells lack Gnrh receptors, but here we show that with time in culture, some Fsh cells start responding to Gnrh, while fshb mRNA levels are significantly reduced, both suggestive of phenotypic change. All together, these results reveal high plasticity of gonadotropes due to both estradiol-sensitive proliferation and Gnrh promoted phenotypic conversion, and moreover, show that gonadotropes lose part of their identity when kept in cell culture.
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Rejzek, Martin, Marie Zarevúcka, Zdeněk Wimmer, Tomáš Vaněk, Richard Tykva, Jelena Kuldová, David Šaman, and Blanka Bennettová. "Synthesis of Juvenile Hormone Bioanalogs Derived from 2-(4-Hydroxybenzyl)-6-methylcyclohexanone." Collection of Czechoslovak Chemical Communications 61, no. 4 (1996): 605–14. http://dx.doi.org/10.1135/cccc19960605.
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A new simple approach to isomeric 2-(4-alkoxybenzyl)-6-methylcyclohexanones and the corresponding alcohols and a subsequent synthesis of compounds imitating the action of the insect juvenile hormones is described. Biological activity of the isomeric juvenile hormone bioanalogs differed considerably when tested on the flesh fly (Sarcophaga bullata) and the yellow mealworm (Tenebrio molitor).
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Liu, Suning, Kang Li, Yue Gao, Xi Liu, Weiting Chen, Wei Ge, Qili Feng, Subba R. Palli, and Sheng Li. "Antagonistic actions of juvenile hormone and 20-hydroxyecdysone within the ring gland determine developmental transitions in Drosophila." Proceedings of the National Academy of Sciences 115, no. 1 (December 18, 2017): 139–44. http://dx.doi.org/10.1073/pnas.1716897115.
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In both vertebrates and insects, developmental transition from the juvenile stage to adulthood is regulated by steroid hormones. In insects, the steroid hormone, 20-hydroxyecdysone (20E), elicits metamorphosis, thus promoting this transition, while the sesquiterpenoid juvenile hormone (JH) antagonizes 20E signaling to prevent precocious metamorphosis during the larval stages. However, not much is known about the mechanisms involved in cross-talk between these two hormones. In this study, we discovered that in the ring gland (RG) of Drosophila larvae, JH and 20E control each other’s biosynthesis. JH induces expression of a Krüppel-like transcription factor gene Kr-h1 in the prothoracic gland (PG), a portion of the RG that produces the 20E precursor ecdysone. By reducing both steroidogenesis autoregulation and PG size, high levels of Kr-h1 in the PG inhibit ecdysteriod biosynthesis, thus maintaining juvenile status. JH biosynthesis is prevented by 20E in the corpus allatum, the other portion of the RG that produces JH, to ensure the occurrence of metamorphosis. Hence, antagonistic actions of JH and 20E within the RG determine developmental transitions in Drosophila. Our study proposes a mechanism of cross-talk between the two major hormones in the regulation of insect metamorphosis.
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Kolbe, Thomas, Sarjoun Sheety, Ingrid Walter, Rupert Palme, and Thomas Rülicke. "Impact of superovulation and mating on the wellbeing of juvenile and adult C57BL/6N mice." Reproduction, Fertility and Development 28, no. 7 (2016): 969. http://dx.doi.org/10.1071/rd14372.
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Superovulation of mice is routinely used to increase the number of obtainable ova per female. Because of the better outcome, prepubescent females are preferentially used. Here, we provide results of the impact of superovulation and mating on the wellbeing of juvenile compared with adult C57BL/6N mice. Two groups of mice (3–4 weeks vs 7–8 weeks old) were superovulated and mated. Observation of mating behaviour showed that reluctant adult females tended to fight the male’s approach, whereas juveniles preferred to take flight. Faeces were collected daily for the analysis of stress hormones. There was no difference in the levels of glucocorticoid metabolites either between age groups or between treated animals and their controls. Histology after mating revealed intact vaginal mucosa without any detectable lesions in all animals regardless of age. In contrast to adults, almost all juveniles were synchronised in oestrus and produced significantly more ova. Taken together, our results reveal no increased welfare problem from using juvenile mice for superovulation and mating. Considering the higher yield of fertilisable oocytes and zygotes, it is advisable to use C57BL/6N prepubescent mice in order to reduce the number of donor females required.
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Kotaki, Toyomi, Tetsuro Shinada, and Hideharu Numata. "Structure Determination of a Natural Juvenile Hormone Isolated from a Heteropteran Insect." Psyche: A Journal of Entomology 2012 (2012): 1–7. http://dx.doi.org/10.1155/2012/924256.
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Juvenile hormone (JH), which occurs in several forms in different insects, is one of the most important insect hormones. The structure of JH in Heteroptera has not been elucidated until recently, although insects in this suborder have long been used as experimental animals for JH research. Here we review the structure determination of a novel JH in a stink bug,Plautia stali, which was named juvenile hormone III skipped bisepoxide [JHSB3: methyl (2R,3S,10R)-2,3;10,11-bisepoxyfarnesoate], based on the arrangement of two epoxides at C2,3 and C10,11 with a skipped double bond at C6,7.
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Hare, Alexander J., Ahmed Waheed, James F. Hare, and W. Gary Anderson. "Cortisol and catecholamine responses to social context and a chemical alarm signal in juvenile lake sturgeon, Acipenser fulvescens." Canadian Journal of Zoology 93, no. 8 (August 2015): 605–13. http://dx.doi.org/10.1139/cjz-2015-0045.
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We examined potential benefits of group living in juvenile lake sturgeon (Acipenser fulvescens Rafinesque, 1817) and whether those benefits applied equally to associations with conspecific and allospecific individuals. In the first experiment, one focal lake sturgeon was placed with either seven size-matched conspecifics, allospecifics, or in isolation and given a 30 s air exposure. In the second experiment, one focal lake sturgeon was placed with either seven conspecifics or in isolation and was exposed to a conspecific skin homogenate as a potential alarm substance or a control of distilled water. Cortisol, norepinephrine, and epinephrine levels were measured before and after exposure in each experiment via an indwelling cannula in the caudal sinus. In the first experiment, lake sturgeon held with allospecifics and in isolation had a significantly longer norepinephrine response. Furthermore, plasma norepinephrine concentration in the focal lake sturgeon in the allospecific treatment was significantly higher than the other treatments following air exposure. In the second experiment, there was no behavioural or hormonal response to the introduction of conspecific skin homogenate, yet isolated fish had elevated baseline norepinephrine and cortisol levels. Finally, comparison of baseline levels of all three hormones between two ages of juveniles indicated an effect of age on baseline epinephrine levels. Our findings confirm the potential physiological benefit of group living in lake sturgeon and suggest an ontogenetic shift in both the behavioural response to potential stressors and the baseline hormonal levels that may influence fitness.
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Woda, Craig B., Nabil Halaihel, Paul V. Wilson, Aviad Haramati, Moshe Levi, and Susan E. Mulroney. "Regulation of renal NaPi-2 expression and tubular phosphate reabsorption by growth hormone in the juvenile rat." American Journal of Physiology-Renal Physiology 287, no. 1 (July 2004): F117—F123. http://dx.doi.org/10.1152/ajprenal.00357.2002.
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Growth hormone (GH) is an important factor in the developmental adaptation to enhance Pi reabsorption; however, the nephron sites and mechanisms by which GH regulates renal Pi uptake remain unclear and are the focus of the present study. Micropuncture experiments were performed after acute thyroparathyroidectomy in the presence and absence of parathyroid hormone (PTH) in adult (14- to 17-wk old), juvenile (4-wk old), and GH-suppressed juvenile male rats. While the phosphaturic effect of PTH was blunted in the juvenile rat compared with the adult, suppression of GH in the juvenile restored fractional Pi excretion to adult levels. In the presence or absence of PTH, GH suppression in the juvenile rat caused a significant increase in the fractional Pi delivery to the late proximal convoluted (PCT) and early distal tubule, so that delivery was not different from that in adults. These data were confirmed by Pi uptake studies into brush-border membrane (BBM) vesicles. Immunofluorescence studies indicate increased BBM type IIa NaPi cotransporter (NaPi-2) expression in the juvenile compared with adult rat, and GH suppression reduced NaPi-2 expression to levels observed in the adult. GH replacement in the [ N-acetyl-Tyr1-d-Arg2]-GRF-(1-29)-NH2-treated juveniles restored high NaPi-2 expression and Pi uptake. Together, these novel results demonstrate that the presence of GH in the juvenile animal is crucial for the early developmental upregulation of BBM NaPi-2 and, most importantly, describe the enhanced Pi reabsorption along the PCT and proximal straight nephron segments in the juvenile rat.
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Maddalozzo, John, Louis T. Tenta, Lewis R. Hutchinson, Susan E. Crawford, and Daniel S. Morse. "Juvenile fibromatosis: hormonal receptors." International Journal of Pediatric Otorhinolaryngology 25, no. 1-3 (January 1993): 191–99. http://dx.doi.org/10.1016/0165-5876(93)90053-6.
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Teulier, Loic, Cyril Dégletagne, Benjamin Rey, Jérémy Tornos, Céline Keime, Marc de Dinechin, Mireille Raccurt, Jean-Louis Rouanet, Damien Roussel, and Claude Duchamp. "Selective upregulation of lipid metabolism in skeletal muscle of foraging juvenile king penguins: an integrative study." Proceedings of the Royal Society B: Biological Sciences 279, no. 1737 (February 22, 2012): 2464–72. http://dx.doi.org/10.1098/rspb.2011.2664.
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The passage from shore to marine life of juvenile penguins represents a major energetic challenge to fuel intense and prolonged demands for thermoregulation and locomotion. Some functional changes developed at this crucial step were investigated by comparing pre-fledging king penguins with sea-acclimatized (SA) juveniles ( Aptenodytes patagonicus ). Transcriptomic analysis of pectoralis muscle biopsies revealed that most genes encoding proteins involved in lipid transport or catabolism were upregulated, while genes involved in carbohydrate metabolism were mostly downregulated in SA birds. Determination of muscle enzymatic activities showed no changes in enzymes involved in the glycolytic pathway, but increased 3-hydroxyacyl-CoA dehydrogenase, an enzyme of the β-oxidation pathway. The respiratory rates of isolated muscle mitochondria were much higher with a substrate arising from lipid metabolism (palmitoyl- l -carnitine) in SA juveniles than in terrestrial controls, while no difference emerged with a substrate arising from carbohydrate metabolism (pyruvate). In vivo , perfusion of a lipid emulsion induced a fourfold larger thermogenic effect in SA than in control juveniles. The present integrative study shows that fuel selection towards lipid oxidation characterizes penguin acclimatization to marine life. Such acclimatization may involve thyroid hormones through their nuclear beta receptor and nuclear coactivators.
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Darrouzet, Eric, Bernard Mauchamp, Glenn D. Prestwich, Lucien Kerhoas, István Ujváry, and Franck Couillaud. "Hydroxy Juvenile Hormones: New Putative Juvenile Hormones Biosynthesized by Locust Corpora Allatain Vitro." Biochemical and Biophysical Research Communications 240, no. 3 (November 1997): 752–58. http://dx.doi.org/10.1006/bbrc.1997.7739.
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Muratova, S. T. "Diagnosed changes of bone mineral density and level of calciotropic hormones in children with juvenile hyperthyroidism." Modern pediatrics. Ukraine, no. 3(115) (April 27, 2021): 23–30. http://dx.doi.org/10.15574/sp.2021.115.23.
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The development of the skeletal system occur during childhood. Thyroid hormones play an important role in the skeleton's maturation and maintenance of the structure and mass of bones. Juvenile hyperthyroidism affects bone metabolism. This study aimed to identify abnormalities in bone mineral density and the level of calciotropic hormones in juvenile hyperthyroidism to further improve the diagnosis of complications of juvenile hyperthyroidism. Materials and methods. The study was conducted by 21 health controls and 71 children and adolescents with juvenile hyperthyroidism. Anthropometric indicators were calculated using the WHO Anthro Plus personal computer software. Thyroid status and thyroid antibodies, osteocalcin, parathyroid hormone, vitamin D, calcium, phosphorus, alkaline phosphatase were determined using a closed-type immunochemistry analyzer Cobas e 411 Hitachi company Hoffman Le Roche (Switzerland) and its reagents. Bone mineral density was evaluated by dual-energy absorptiometry on a Stratos X-ray densitometer from Diagnostic Medical Systems, France. Results. In juvenile hypertrichosis, in comparison with the control, significantly low values of vitamin D and calcium in the blood serum were noted, the mean values of osteocalcin and alkaline phosphatase were substantially higher. There was no significant difference in the levels of parathyroid hormone and phosphorus in the blood serum in the compared groups. In 45.1% of patients, a decrease in bone mass was diagnosed compared to the age norm. A reliable direct correlation of vitamin D and calcium with bone density was revealed in all X-ray densitometry parameters and a reliable inverse correlation of osteocalcin, alkaline phosphatase and bone mineral density. Osteocalcin had a stronger inverse correlation with all dual-energy X-ray absorptiometry parameters and became a better biomarker than alkaline phosphatase. Conclusions. There is a decrease in bone mineral density in children with juvenile hyperthyroidism. Changes in the level of calciotropic hormones indicate a deranged bone metabolism. Serum osteocalcin can be used as a biomarker of bone metabolism in children with juvenile hyperthyroidism. It is recommended to assess the bones' condition during the initial examination of children with juvenile hyperthyroidism. The study was carried out following the principles of the Declaration of Helsinki. The study protocol was approved by the Local Ethics Committee of the participating institution. The informed consent of the parents of the children was obtained for the research. The author declares no conflicts of interest. Key words: juvenile hyperthyroidism, children, adolescents, bone mineral density; dual energy X-ray absorptiometry, osteocalcin, vitamin D.
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Gade, G., K. H. Hoffmann, and J. H. Spring. "Hormonal regulation in insects: facts, gaps, and future directions." Physiological Reviews 77, no. 4 (October 1, 1997): 963–1032. http://dx.doi.org/10.1152/physrev.1997.77.4.963.
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There are two main classes of hormones in insects: 1) the true hormones produced by epithelial glands and belonging to the ecdysteroids or juvenile hormones and 2) the neuropeptide hormones produced by neurosecretory cells. Members of these classes regulate physiological, developmental, and behavioral events in insects. Detailed accounts are given on isolation, identification, structure-activity relationships, mode of action, biological function, biosynthesis, inactivation, metabolism, and feedback for hormones involved in 1) metabolic regulation such as the adipokinetic/hypertrehalosemic peptides and the diuretic and antidiuretic peptides; 2) stimulation or inhibition of muscle activity such as the myotropic peptides; 3) control of reproduction, growth, and development such as allatotropins, allatostatins, juvenile hormones, ecdysteroids, folliculostimulins and folliculostatins, ecdysis-triggering and eclosion hormones, pheromone biosynthesis activating neuropeptides, and diapause hormones; and 4) regulation of tanning and of color change. Because of the improvements in techniques for isolation and structure elucidation, there has been rapid progress in our knowledge of the chemistry of certain neuropeptide families. With the employment of molecular biological techniques, the genes of some neuropeptides have been successfully characterized. There are, however, areas that are still quite underdeveloped. These are, for example, 1) receptor studies, which are still in their infancy; 2) the hormonal status of certain sequenced peptides is not clarified; and 3) functional studies are lacking even for established hormones. The authors plead for a concerted effort to continue research in this field, which will also advance our knowledge into the use of insect hormones as safer and species-specific molecules for insect pest management.
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Ferenz, Hans-Jörg, and Elke Aden. "Kontrolle der Juvenilhormon-Biosynthese durch das Ovar bei Locusta migratoria (Orthoptera): Acrididae)." Entomologia Generalis 18, no. 1-2 (June 1, 1993): 9–17. http://dx.doi.org/10.1127/entom.gen/18/1993/9.
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Yang, Huipeng, and Jie Wu. "Comparison of Predicted Amino Acid Sequences of Allatotropin/Allatostatin Receptors from Solitary to Eusocial Bee Species (Hymenoptera, Apoidea)." Journal of Apicultural Science 63, no. 2 (December 1, 2019): 267–79. http://dx.doi.org/10.2478/jas-2019-0021.
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AbstractAn increasingly amount of evidence supports that the evolution of eusociality is accompanies by shifts in ancient molecular and physiological pathways. The juvenile hormone, one of the most important hormones in the post-embryonic development of insects, attracts the most attention in the context of social organization. Allatoregulatory neuropeptides (Allatotropin, Allatostatin-A and Allatostatin-C) are known to regulate juvenile hormone synthesis and release in insects. In order to clarify the transitions of juvenile hormone synthesis involved in eusocial evolution, the substitutions of amino acid residues and the complexity of post-translational modifications in allatoregulatory neuropeptide receptors were characterized. Both allatotropin and allatostatin receptors are identified in all examined bee species regardless if they are solitary or eusocial. Although the amino acid sequences are highly conserved, phylogenetic results are consistent with the eusocial status. The abundance of predicted post-translational modifications correlates with social complexity except for that in allatostatin-C receptors. Even though the consequences of these specific amino acid substitutions and various post-translational modification complexity have not been studied, they likely contribute to the localizing, binding and coupling characteristics of the receptor groups.
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Lewis, S. E., A. Yokofich, M. Mohr, C. Kurth, R. Giuliani, and M. G. Baldridge. "Exposure to bisphenol A modulates hormone concentrations in Gammarus pseudolimnaeus." Canadian Journal of Zoology 90, no. 12 (December 2012): 1414–21. http://dx.doi.org/10.1139/cjz-2012-0178.
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Bisphenol A (BPA) is an endocrine-disrupting compound that can enter aquatic systems through landfill leachate or wastewater effluent. Although impacts of BPA on vertebrates are well documented, its effects on invertebrates are less clear. Amphipods such as Gammarus pseudolimnaeus Bousfield, 1958 are often prevalent invertebrates in freshwater ecosystems and can provide a powerful invertebrate model system to investigate the endocrine-disruptive capabilities of BPA. However, techniques to assay hormone concentrations in amphipods, especially vertebrate-like steroid sex hormones, are not widespread. In this study, we (i) quantified estrogen concentrations in juveniles and in adult female amphipods; (ii) quantified testosterone concentrations in juveniles and in adult male amphipods; and (iii) delineated changes to estrogen and testosterone concentrations of adults and juveniles following a 9-day exposure to BPA at four levels: 0 (control), 10, 50, and 100 µg/L BPA. Tissue extracts from homogenized samples were analyzed for estrogen or testosterone concentrations via radioimmunoassay for each reproductive class of amphipod. Low concentrations of BPA significantly increased estrogen concentrations in adult females and in juveniles. Moderate and high concentrations of BPA significantly increased testosterone concentrations in adult males, and low and moderate concentrations of BPA significantly increased testosterone concentrations of juveniles.
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Calcaterra, Valeria, Ghassan Nakib, Gloria Pelizzo, Barbara Rundo, Gaetana Anna Rispoli, Stella Boghen, Federico Bonetti, Barbara Del Monte, Chiara Gertosio, and Daniela Larizza. "Central precocious puberty and granulosa cell ovarian tumor in an 8-year old female." Pediatric Reports 5, no. 3 (July 29, 2013): 13. http://dx.doi.org/10.4081/pr.2013.e13.
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Ovarian tumors associated with hormonal changes of the peripheral iso-sexual precocious puberty are of common presentation. We describe here a rare case of juvenile granulosa cell tumor in a female with central precocious puberty (CPP). An 8-year old girl with CPP presented with vaginal bleeding four months after the diagnosis and before starting treatment with gonadotropin-releasing hormone (GnRH)-analogs. Suppression of basal follicle-stimulating hormone (FSH) level, elevation of serum estradiol, progesterone and Cancer Antigen-125 were documented. Abdominal ultrasound examination (US) and magnetic resonance imaging showed a pelvic mass affecting the left ovary. A left salpingo-oophorectomy was performed and the mass was totally resected. Juvenile granulosa cell ovarian tumor was diagnosed. One month post surgery, estradiol and progesterone decreased to values of the first evaluation and FSH increased; Cancer Antigen-125 resulted normal while ultrasound pelvic examination showed absence of pelvic masses. In our patient, the tumor had grown very quickly since hormonal data demonstrated a CPP without any evidence of ovarian mass on US only four months before diagnosis. The overstimulation of the FSH or aberrant activation of FSH receptors may have contributed to the development of the mass.
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Weeks, J. C., and J. W. Truman. "Hormonally mediated reprogramming of muscles and motoneurones during the larval-pupal transformation of the tobacco hornworm, Manduca sexta." Journal of Experimental Biology 125, no. 1 (September 1, 1986): 1–13. http://dx.doi.org/10.1242/jeb.125.1.1.
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The larval-pupal transformation of Manduca sexta results from an exposure to ecdysteroids in the absence of juvenile hormone (the commitment pulse), followed by a larger exposure to ecdysteroids (the prepupal peak) with a reappearance of juvenile hormone (JH). The prepupal ecdysteroid peak triggers the degeneration of abdominal muscles, and the dendritic regression and death of identified motoneurones. The present experiments examined the role of the commitment pulse in the larval-pupal reprogramming of these cells. The commitment pulse did not overtly affect the muscles and motoneurones, but it switched their hormonal responsiveness; before the commitment pulse, exposure to ecdysteroids in the presence of JH had no effect on the larval cells, whereas after the commitment pulse the same treatment caused regression and death. Thus, JH lost its ability to prevent pupal development. Furthermore, treatment with ecdysteroids in the absence of JH before the commitment pulse promoted pupal development much less effectively than did the same treatment given after the commitment pulse, indicating that the commitment pulse facilitates the subsequent responsiveness to ecdysteroids. Thus, the commitment pulse covertly causes both qualitative and quantitative changes in the hormonal sensitivity of the larval muscles and motoneurones.
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Sláma, Karel. "Insect hormones: more than 50-years after the discovery of insect juvenile hormone analogues (JHA, juvenoids)." Terrestrial Arthropod Reviews 6, no. 4 (March 31, 2013): 257–333. http://dx.doi.org/10.1163/18749836-06041073.
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This review describes the over half-centennial history of research on insect juvenile hormone (JH) as well as its natural and synthetic bioanalogues (JHA or juvenoids).The leading theories of insect hormone action in growth and metamorphosis were created more than 50 years ago by the pioneers of insect endocrinology, V. B. Wigglesworth, C. M. Williams, V. J. A. Novák, H. Piepho, H. A. Schneiderman and L. I. Gilbert. There are two principal categories of hormones released from the central neuroendocrine system (neurosecretory cells of the brain, corpora cardiaca, corpora allata) that regulate insect growth and metamorphosis. The first is a complex set of neurohormones (neuropeptides) originating in the neurosecretory cells of the insect brain, which are released from the neurohaemal organs, the corpora cardiaca. These neuropeptides are responsible for stimulation of various developmental events, such as the release of the activation hormone, AH. The second category of centrally produced hormones in insects is the morphogenesis inhibiting hormone, or juvenile hormone (JH), produced by the associated endocrine glands, the corpora allata. JH is responsible for induction of the somatic larval growth in young instar larvae and stimulation of reproduction in the feeding adult stages.Wigglesworth (1935) first described JH as an inhibitory hormone; Williams (1957) discovered its active extracts. Sláma (1961) discovered the hormonomimetic or pseudojuvenile effects of various lipid extracts and free fatty acids. In addition to lipid extracts with JH activity, a phenomenon found in various human organs, microorganisms and plants, JH-mimetic materials were found in American paper products in 1964. The source of the so-called “paper factor” was the wood of the Canadian balsam fir. The potential use of these and other analogues of JH as nontoxic, selectively acting “third generation pesticides” stimulated an enormous boom of activity among industrial and academic institutions all over the world, in the pursuit of synthetic JH analogues for replacement of toxic insecticides.For practical reasons, in this review the chemical structures of the synthetic juvenoids have been divided into three categories: a) natural and synthetic, predominantly terpenoid juvenoids known before 1970; b) terpenoid and nonterpenoid juvenoids synthesized and tested before 1980, and; c) predominantly nonterpenoid, polycyclic juvenoids with relatively high JH activity, found and selected for practical use after 1980. Chemical structures of several juvenoids of theoretical or practical importance, together with the essential structure-activity relationships, are outlined in several figures and tables. The total number of all juvenoids reported active in one or more insects species has been estimated to be more than 4000 compounds. A juvenoid molecule has, more or less, a similar molecular size, roughly equivalent to a chain of 15 to 17 carbon atoms, with the presence of some slightly polar functional groups and a more or less lipophilic physico-chemical properties. Beyond these similarities, there are many variations in the structural types of juvenoids, including, derivatives of acyclic terpenoids, arylterpenoids, peptides, heterocyclic and polycyclic juvenoids, phenoxyphenyl juvenoids, juvenoid carbamates, and pyridyl-derivatives.In addition to the generally known and intensively studied effects of juvenoids, such as inhibition of metamorphosis, inhibition of embryogenesis, and stimulation of ovarian growth, there are certain less remarkable and largely unexplored biological effects of juvenoids. Some of those phenomena, which are briefly described in this review, are: a) the effects of juvenoids on embryonic development (ovicidal effects); b) delayed effects of JH on metamorphosis from egg stage; c) sexually transmitted female sterility caused by juvenoid treatments of the males; d) the nonvolatile, biochemically activated juvenogen complexes, generating hormonally active juvenoids by enzymatic hydrolysis of the complex, and; e) antihormones with antijuvenile activity.There are two basic hormonal theories on the regulation of insect metamorphosis by JH that have been proposed during the past 50 years. The first is the theory of Gilbert-Riddiford, which has been widely disseminated at universities worldwide, through textbooks on insect physiology, biochemistry and endocrinology. The second, less renowned, hormonal theory of insect development is that of Novák-Sláma. Briefly, the Gilbert-Riddiford theory is based on several fundamental principles. These are: a) the brain hormone-prothoracic gland (PG) concept created more than 50 years ago and later disproved by Williams; b) the conclusions of Piepho, who suggested that a large concentration of JH would cause a single epidermal cell to develop larval patterns, pupal patterns at medium concentrations, and adult epidermal patterns at zero concentration; c) small amounts of JH are necessary in the last larval instars of endopterygote insects for preventing precocious proliferation of imaginal discs; d) metamorphosis is stimulated by PG through a small endogenous peak of ecdysteroid preceding the large prepupal one; e) ecdysteroids are released from the PG in response to superimposed prothoracicotropic hormone (PTTH) from the brain; f) the true juvenile hormone of the corpora allata is a sesquiterpenoid compound known as epoxy homofarnesoate (JH-I), isolated from the adult male abdomens of the Cecropia silkmoths, and; g) physiological functions of JH and other hormones are regulated at the peripheral level by enzymes (esterase) or genes (methoprene tolerant,Metor a Broad complex gene).The Novák-Sláma theory is based on completely different building blocks. Briefly, these are: a) the PG represent a peripheral organ which is not involved in the regulation of the moulting cycles, instead; b) the PG are a subordinated target of JH (not PTTH), they are inactive during the last larval instar and their removal does not abolish the cycles of moults; c) the PG are used to generate metabolic water during the growth of young larval instars by secreting of an adipokinetic superhormone, which stimulates total combustion of the dietary lipids; d) small, medium, or large concentrations of JH are unimportant, the hormone only needs to be present in the minimum, physiologically effective concentrations; e) an imperative condition for metamorphosis to occur is a virtual absence of JH starting from the second half of the penultimate larval instar; f) JH acts according to an “all-or-none” rule at the single cell level, and the temporal sensitivity to JH is strictly limited to a narrow period at the beginning of the moulting cycle, before the cells begin to divide; g) the corpus allatum never produces JH in a nonfeeding stage, and the sesquiterpenoid juvenoid JH-I cannot be the true JH of insects (it has very low JH activity, 100,000-fold smaller in comparison to human made peptidic juvenoids); h) the developmental cycles are stimulated exclusively by neuropeptides produced by the brain’s neurosecretory cells (AH); i) developmental stimulation by AH has nothing in common with the PTTH or PG; j) when environmental interventions in the hormonal system become obsolete, the regulation of moulting cycles becomes autonomic (hormone independent), supported by the stereotypic instructions coded on the genome; k) during the millions of years of insect evolution, the central neuroendocrine system acquired the superimposed, epigenetic ability to adapt gene functions and synchronize them with essential changes in the environment. A model based on the regulation of insect metamorphosis by simple combination of two hormones (AH, JH) of the central neuroendocrine system is outlined. A possibility that the 4000 known juvenoid molecules act as the feedback or homeostatic factors affecting permeability of the epidermal cell membranes has been suggested. Speculations about possible peptidic or proteinic nature of the corpus allatum hormone have been emphasized.
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Gardiner, K. J., I. L. Boyd, B. K. Follett, P. A. Racey, and P. JH Reijnders. "Changes in pituitary, ovarian, and testicular activity in harbour seals (Phoca vitulina) in relation to season and sexual maturity." Canadian Journal of Zoology 77, no. 2 (August 1, 1999): 211–21. http://dx.doi.org/10.1139/z98-211.
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This study examined pituitary sensitivity to exogenous gonadotrophin-releasing hormone (GnRH) in relation to time of year and changes in plasma progesterone, testosterone, luteinising hormone (LH), and follicle-stimulating hormone (FSH) concentrations during the annual cycle of adult and juvenile harbour seals (Phoca vitulina vitulina). There was no significant difference in seasonal changes in reproductive hormone levels between six captive individuals and seals caught from the wild (n = 80). Based on results from both the captive and the wild individuals, the plasma progesterone concentration was elevated in late gestation, whereas it declined at the equivalent time in nonpregnant females. The progesterone concentration was also elevated during the phase of delayed implantation, but there was no difference between pregnant and nonpregnant seals. In captive seals given exogenous GnRH, the LH concentration peaked 10-20 min after injection of GnRH, and the magnitude of the LH response depended upon the dose up to ~120 ng·kg-1. FSH did not respond to GnRH in the time course of the experiment. Pituitary sensitivity to GnRH was greatest in the summer and autumn and lowest in the winter and spring. Seasonal changes in pituitary sensitivity were apparent in both adults and juveniles. There was evidence that three of the four juvenile seals attained puberty during the study. We conclude that the seasonal patterns of pituitary sensitivity and plasma hormone concentration in harbour seals are consistent with a reproductive cycle under photoperiodic control and with the general mechanisms underlying photoperiodic control of seasonal reproduction in higher vertebrates.
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Varnavsky, Vladimir S., Tatsuya Sakamoto, and Tetsuya Hirano. "Stunting of Wild Coho Salmon (Oncorhynchus kisutch) in Seawater: Patterns of Plasma Thyroid Hormones, Cortisol, and Growth Hormone." Canadian Journal of Fisheries and Aquatic Sciences 49, no. 3 (March 1, 1992): 458–61. http://dx.doi.org/10.1139/f92-054.
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Under natural conditions, some coho salmon presmolts (Oncorhynchus kisutch) in Kamchatka have been observed to migrate prematurely to the sea and fail to grow in brackish water for prolonged periods (natural stunts). Plasma levels of growth hormone, cortisol, thyroxine, and triiodothyronine were measured in coho salmon parr captured in the river (freshwater), smolts migrating downstream captured at the river mouth (brackish water), smolts in the sea (seawater), and natural stunts in the inlet (brackish water). The physiological conditions of natural stunts seem analogous to those of hatchery-derived stunts observed in hatchery-reared juveniles in sea pens, with normal plasma sodium concentration, low levels of thyroid hormones and cortisol, and high growth hormone levels.
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REES, H. H. "Hormonal control of tick development and reproduction." Parasitology 129, S1 (October 2004): S127—S143. http://dx.doi.org/10.1017/s003118200400530x.
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Ecdysteroids (moulting hormones), juvenoids and neuropeptides in ticks are reviewed but, by far, the emphasis is on the former since this class of hormones has been the subject of most investigations. In immature stages of ticks, ecdysteroids have been shown to regulate moulting and to terminate larval diapause. Although there is a paucity of information on the molecular action of ecdysteroids in ticks, their action appears to be via a heterodimeric ecdysone/ultraspiracle receptor, as in insects. The role of ecdysteroids in sperm maturation in adult males is considered. In females, ecdysteroids function in the regulation of salivary glands, of production of sex pheromones and of oogenesis and oviposition. There is evidence for ecdysteroid production in the integument and pathways of hormone inactivation are similar to those in insects. Ecdysteroids also function in embryogenesis. Although evidence for the occurrence and functioning of juvenile hormones in ticks has been contradictory, in recent thorough work it has not been possible to detect known juvenile hormones in ticks, nor to demonstrate effects of extracts on insects. Factors (neuropeptides) from the synganglion affect physiological processes and limited immunocytochemical studies are reviewed. Sigificantly, a G-protein-coupled receptor has been cloned, expressed, and specifically responds to myokinins.
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Bownes, M., A. Scott, and A. Shirras. "Dietary components modulate yolk protein gene transcription in Drosophila melanogaster." Development 103, no. 1 (May 1, 1988): 119–28. http://dx.doi.org/10.1242/dev.103.1.119.
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The three yolk proteins of Drosophila melanogaster begin to be synthesized at eclosion. Transcription of the genes is regulated by the genes tra, tra-2 and dsx and also by the insect hormones, juvenile hormone and 20-hydroxyecdysone. We show that there is yet another level of control which is dependent upon feeding. Females that are starved from eclosion show a basal level of yolk protein gene transcription, which is rapidly increased when a complete diet is supplied. We show that the effect is not due to incorrect development of the fat body and is unlikely to be solely due to a general effect on protein synthesis. Later in development, cessation of feeding leads to selective inhibition of yolk protein synthesis and hence egg production. The effects of starvation can be partially overcome by 20-hydroxyecdysone, juvenile hormone, casein, amino acid mix or sucrose, but only a complete medium or live yeast brings about total recovery. Using yp1-Adh fusions (fusions of the promoter region of yp1 to the structural gene for Adh), the DNA sequence required for this diet-enhanced transcription has been located within an 890 bp fragment upstream of the yp1 gene. The insect hormones do not operate on this same DNA fragment.
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Wimmer, Zdeněk, and Miroslav Romaňuk. "Insect juvenile hormones and their bioanalogues." Collection of Czechoslovak Chemical Communications 54, no. 9 (1989): 2302–29. http://dx.doi.org/10.1135/cccc19892302.
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This survey supplements and up-dates review articles of other authors published in the field of substances affecting the development of the insect, juvenoids. Attention has been paid primarily to such structures as deserved more detailed investigation in the given field owing to their biological properties, further to less known structures and facts, and lastly to the most recent information from literature, mainly paying attention to the present trend in searching for structural types of substances affecting insect development. The synthetic juvenoids discussed are divided into chapters, on the basis of the skeleton of the molecule, on aliphatic juvenoids, juvenoids with one aromatic ring in the molecule and finally juvenoids with two and more cycles (aromatic as well as non-aromatic) in the molecule. Certain attention has also been paid to optically active juvenoids. Finally the role is mentioned of complex hormonogen compounds, juvenogens, in the protection of cultured plants against economically important insect pests.
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FARAG, M. MOKHTAR, S. E. GHANIMAH, A. RAGAIE, and T. H. SALEEM. "HORMONAL RECEPTORS IN JUVENILE NASOPHARYNGEAL ANGIOFIBROMA." Laryngoscope 97, no. 2 (February 1987): 208???211. http://dx.doi.org/10.1288/00005537-198702000-00013.
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Salis, Pauline, Natacha Roux, Delai Huang, Anna Marcionetti, Pierick Mouginot, Mathieu Reynaud, Océane Salles, et al. "Thyroid hormones regulate the formation and environmental plasticity of white bars in clownfishes." Proceedings of the National Academy of Sciences 118, no. 23 (May 24, 2021): e2101634118. http://dx.doi.org/10.1073/pnas.2101634118.
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Determining how plasticity of developmental traits responds to environmental conditions is a challenge that must combine evolutionary sciences, ecology, and developmental biology. During metamorphosis, fish alter their morphology and color pattern according to environmental cues. We observed that juvenile clownfish (Amphiprion percula) modulate the developmental timing of their adult white bar formation during metamorphosis depending on the sea anemone species in which they are recruited. We observed an earlier formation of white bars when clownfish developed with Stichodactyla gigantea (Sg) than with Heteractis magnifica (Hm). As these bars, composed of iridophores, form during metamorphosis, we hypothesized that timing of their development may be thyroid hormone (TH) dependent. We treated clownfish larvae with TH and found that white bars developed earlier than in control fish. We further observed higher TH levels, associated with rapid white bar formation, in juveniles recruited in Sg than in Hm, explaining the faster white bar formation. Transcriptomic analysis of Sg recruits revealed higher expression of duox, a dual oxidase implicated in TH production as compared to Hm recruits. Finally, we showed that duox is an essential regulator of iridophore pattern timing in zebrafish. Taken together, our results suggest that TH controls the timing of adult color pattern formation and that shifts in duox expression and TH levels are associated with ecological differences resulting in divergent ontogenetic trajectories in color pattern development.
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Chanchay, Pornchanan, Wanwipa Vongsangnak, Anchana Thancharoen, and Ajaraporn Sriboonlert. "Reconstruction of insect hormone pathways in an aquatic firefly, Sclerotia aquatilis (Coleoptera: Lampyridae), using RNA-seq." PeerJ 7 (August 2, 2019): e7428. http://dx.doi.org/10.7717/peerj.7428.
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Insect hormones: ecdysteroids and juvenile hormones have crucial functions during the regulation of different developmental pathways in insects. Insect metamorphosis is one of the primary pathways regulated by these hormones. The insect hormone biosynthetic pathway is conserved among arthropods, including insects, with some variations in the form of hormones used among each group of insects. In this study, the candidate genes involved in the insect hormone pathways and their functional roles were assessed in an aquatic firefly, Sclerotia aquatilis using a high-throughput RNA sequencing technique. Illumina next-generation sequencing (NGS) was used to generate transcriptome data for the different developmental stages (i.e., larva, pupa, and adult) of S. aquatilis. A total of 82,022 unigenes were generated across all different developmental stages. Functional annotation was performed for each gene, based on multiple biological databases, generating 46,230 unigenes. These unigenes were subsequently mapped using KEGG pathways. Accordingly, 221 protein-encoding genes involved in the insect hormone pathways were identified, including, JHAMT, CYP15A1, JHE, and Halloween family genes. Twenty potential gene candidates associated with the biosynthetic and degradation pathways for insect hormones were subjected to real-time PCR, reverse transcriptase PCR (RT-PCR) and sequencing analyses. The real-time PCR results showed similar expression patterns as those observed for transcriptome expression profiles for most of the examined genes. RT-PCR and Sanger sequencing confirmed the expressed coding sequences of these gene candidates. This study is the first to examine firefly insect hormone pathways, facilitating a better understanding of firefly growth and development.
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Kethidi, Damodar R., Srini C. Perera, S. Zheng, Qi-Li Feng, Peter Krell, Arthur Retnakaran, and Subba R. Palli. "Identification and Characterization of a Juvenile Hormone (JH) Response Region in the JH Esterase Gene from the Spruce Budworm,Choristoneura fumiferana." Journal of Biological Chemistry 279, no. 19 (February 27, 2004): 19634–42. http://dx.doi.org/10.1074/jbc.m311647200.
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Using a differential display of mRNA technique we discovered that the juvenile hormone (JH) esterase gene (Cfjhe) fromChoristoneura fumiferanais directly induced by juvenile hormone I (JH I), and the JH I induction is suppressed by 20-hydroxyecdysone (20E). To study the mechanism of action of these two hormones in the regulation of expression of this gene, we cloned the 1270-bp promoter region of the Cfjhe gene and identified a 30-bp region that is located between –604 and –574 and is sufficient to support both JH I induction and 20E suppression. This 30-bp region contains two conserved hormone response element half-sites separated by a 4-nucleotide spacer similar to the direct repeat 4 element and is designated as a putative juvenile hormone response element (JHRE). In CF-203 cells, a luciferase reporter placed under the control of JHRE and a minimal promoter was induced by JH I in a dose- and time-dependent manner. Moreover, 20E suppressed this JH I-induced luciferase activity in a dose- and time-dependent manner. Nuclear proteins isolated from JH I-treated CF-203 cells bound to JHRE and the binding was competed by a 100-fold excess of the cold probe but not by 100-fold excess of double-stranded oligonucleotides of unrelated sequence. JH I induced/modified nuclear proteins prior to their binding to JHRE and 20E suppressed this JH I induction/modification. These results suggest that the 30-bp JHRE identified in the Cfjhe gene promoter is sufficient to support JH induction and 20E suppression of the Cfjhe gene.
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Chatrath, Ritu, Karen L. Ronningen, Sandra R. Severson, Peter LaBreche, Muthuvel Jayachandran, Margarita P. Bracamonte, and Virginia M. Miller. "Endothelium-dependent responses in coronary arteries are changed with puberty in male pigs." American Journal of Physiology-Heart and Circulatory Physiology 285, no. 3 (September 2003): H1168—H1176. http://dx.doi.org/10.1152/ajpheart.00029.2003.
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In humans, cardiovascular disease begins in young adulthood and is more prevalent in males than females. However, little is known about vascular function during transition to adulthood in males. The aim of this study was to define changes in production of endothelium-derived nitric oxide (NO) and coronary arterial responses during puberty. Plasma was collected from juvenile (2–3 mo of age) and adult (5–6 mo of age) male pigs ( n = 8/group) for measurement of NO, and aortic endothelial cells were collected for measurement of mRNA and protein for endothelial NO synthase (eNOS). Although plasma NO was higher in juvenile (67.0 ± 25.6 μM) than in adult (15.0 ± 7.1 μM) male pigs, eNOS protein was similar in both groups. However, levels of mRNA for eNOS were lower in aortic endothelial cells from juvenile pigs. In rings of coronary arteries suspended in organ chambers for measurement of isometric force and contracted with PGF2α, relaxations to an α2-adrenergic agonist were significantly inhibited by indomethacin only in juvenile pigs [EC50 (–log M), 6.7 ± 0.3 with indomethacin and 7.7 ± 0.3 under control conditions]. NG-monomethyl-l-arginine (l-NMMA) inhibited relaxations in both groups. On the contrary, in the presence of indomethacin, relaxations to bradykinin were inhibited by l-NMMA only in arteries from adult pigs [EC50 (–log M), 8.9 ± 0.3 with indomethacin and 8.6 ± 0.3 with addition of l-NMMA]. These results suggest that hormonal changes associated with sexual maturity may affect posttranscriptional and/or translational regulation of eNOS protein and result in lower plasma NO in adult male pigs. In addition, endothelium-derived inhibitory cyclooxygenase products seem to predominate in juveniles.
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Lyu, Zihao, Zhixing Li, Jie Cheng, Chunyan Wang, Jingxiang Chen, and Tong Lin. "Suppression of Gene Juvenile Hormone Diol Kinase Delays Pupation in Heortia vitessoides Moore." Insects 10, no. 9 (September 2, 2019): 278. http://dx.doi.org/10.3390/insects10090278.
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Juvenile hormone diol kinase (JHDK) is a critical enzyme involved in juvenile hormone degradation in insects. In this study, HvJHDK in the Heortia vitessoides Moore (Lepidoptera: Crambidae) transcriptional library was cloned. Stage-specific expression patterns of HvJHDK, HvJHEH, and HvJHE as well as juvenile hormone titers were determined. The three tested enzymes participated in juvenile hormone degradation. Moreover, juvenile hormone titers peaked after larval–larval molts, consistent with a role for juvenile hormone in inhibition of metamorphosis. HvJHDK was subsequently suppressed using RNA interference (RNAi) to reveal its functions. Different concentrations of dsJHDK elicited the optimal interference efficiency at different life stages of H. vitessoides. Suppression of HvJHDK decreased HvJHDK content and increased the juvenile hormone titer, thereby resulting in reduced triglyceride content, sharply declined survival rate, clearly lethal phenotypes, and extended larval growth. Moreover, suppression of HvJHDK upregulated HvJHEH and HvJHE expression levels, suggesting that there is feedback regulation in the juvenile hormone metabolic pathway. Taken together, our findings provide molecular references for the selection of novel insecticidal targets.
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Livingston, Frederick S., and Richard Mooney. "Androgens and Isolation From Adult Tutors Differentially Affect the Development of Songbird Neurons Critical to Vocal Plasticity." Journal of Neurophysiology 85, no. 1 (January 1, 2001): 34–42. http://dx.doi.org/10.1152/jn.2001.85.1.34.
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Song learning in oscine birds occurs during a juvenile sensitive period. One idea is that this sensitive period is regulated by changes in the electrophysiological properties of neurons in the telencephalic song nucleus lateral magnocellular nucleus of the anterior neostriatum (LMAN), a structure critical for song development but not adult singing. A corollary of this idea is that manipulations affecting the pace and quality of song learning will concomitantly affect the development of LMAN′s electrophysiological properties. Manipulations known to affect song development include treating juvenile male zebra finches with exogenous androgens, which results in abnormally truncated adult songs, and isolation of the juvenile from adult tutors and their songs, which extends the sensitive period for song learning. Previously, we showed that synaptic transmission in LMAN changes over normal song development and that these changes are accelerated or retarded, respectively, by androgen treatment and isolation from an adult tutor. The intrinsic properties of LMAN neurons afford another potential target for regulation by steroid hormones and experience of adult tutors. Indeed previous studies showed that the capacity for LMAN neurons to fire action potentials in bursts, due to a low-threshold calcium spike, and the width of single action potentials in LMAN, wane over development. Here we analyzed these and other intrinsic electrophysiological features of LMAN neurons over normal development, then tested whether either early androgen treatment or isolating juveniles from adult tutors affected the timing of these changes. The present study shows that androgen but not isolation treatment alters the developmental time at which LMAN neurons progress from the bursting to nonbursting phenotype. In addition, other intrinsic properties, including the half-height spike width and the magnitude of the spike afterhyperpolarization (AHP), were found to change markedly over development but only changes to the AHP were androgen sensitive. Interestingly of all of the synaptic and intrinsic electrophysiological properties in LMAN studied to date, only the half-height spike width continues to change in the late juvenile stages of song learning. Furthermore raising juveniles in isolation from an adult tutor transiently delays the maturation of this property. The present results underscore that beyond their effects on LMAN′s synaptic properties, both androgens and adult tutor experience are potent and selective regulators of the intrinsic properties of LMAN neurons.
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Applebaum, Shalom W., and Noelle A. Granger. "Seventh International Conference on the Juvenile Hormones." Insect Biochemistry and Molecular Biology 30, no. 8-9 (September 2000): 615. http://dx.doi.org/10.1016/s0965-1748(00)00033-3.
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Kumagami, Hidetaka. "Sex Hormones in Juvenile Nasopharyngeal Angiofibroma Tissue." Auris Nasus Larynx 20, no. 2 (January 1993): 131–35. http://dx.doi.org/10.1016/s0385-8146(12)80240-9.
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Doumandji, Lotfi, Hubert Matondo, Sébastien Estaran, Boudjema Hamada, Christophe Lagneau, James Devillers, André Yébakima, Annick Doucet-Panaye, Jean-Pierre Doucet, and Armand Lattes. "Synthesis of retinoid analogues of juvenile hormones." Applied Organometallic Chemistry 31, no. 10 (February 20, 2017): e3736. http://dx.doi.org/10.1002/aoc.3736.
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Weaver, Robert J., Neil Audsley, and Howard A. Bell. "Ninth International Conference on the Juvenile Hormones." Journal of Insect Physiology 54, no. 6 (June 2008): 893–94. http://dx.doi.org/10.1016/j.jinsphys.2008.04.014.
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Bodemann, René Roberto, Peter Rahfeld, Magdalena Stock, Maritta Kunert, Natalie Wielsch, Marco Groth, Sindy Frick, Wilhelm Boland, and Antje Burse. "Precise RNAi-mediated silencing of metabolically active proteins in the defence secretions of juvenile leaf beetles." Proceedings of the Royal Society B: Biological Sciences 279, no. 1745 (August 8, 2012): 4126–34. http://dx.doi.org/10.1098/rspb.2012.1342.
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Allomones are widely used by insects to impede predation. Frequently these chemical stimuli are released from specialized glands. The larvae of Chrysomelina leaf beetles produce allomones in gland reservoirs into which the required precursors and also the enzymes are secreted from attached gland cells. Hence, the reservoirs can be considered as closed bio-reactors for producing defensive secretions. We used RNA interference (RNAi) to analyse in vivo functions of proteins in biosynthetic pathways occurring in insect secretions. After a salicyl alcohol oxidase was silenced in juveniles of the poplar leaf beetles, Chrysomela populi , the precursor salicyl alcohol increased to 98 per cent, while salicyl aldehyde was reduced to 2 per cent within 5 days. By analogy, we have silenced a novel protein annotated as a member of the juvenile hormone-binding protein superfamily in the juvenile defensive glands of the related mustard leaf beetle, Phaedon cochleariae . The protein is associated with the cyclization of 8-oxogeranial to iridoids (methylcyclopentanoid monoterpenes) in the larval exudates made clear by the accumulation of the acylic precursor 5 days after RNAi triggering. A similar cyclization reaction produces the secologanin part of indole alkaloids in plants.
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Cook, Harry, Andrew Zuidhof, Toyoji Kaneko, Hao-Ren Lin, Mei Li Zhang, and Richard E. Peter. "Somatotrop, gonadotrop, and prolactin cells in the pars distalis of juvenile grass carp (Ctenopharyngodon idellus): an immunocytochemical study." Canadian Journal of Zoology 69, no. 3 (March 1, 1991): 803–6. http://dx.doi.org/10.1139/z91-117.
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The grass carp (Ctenopharyngodon idellus) is an important aquaculture species which is grown in many areas of the world. Because the species is the focus of basic and applied endocrinological studies, it is important to establish whether antibodies raised against common carp hormones will recognize hormones of the grass carp. Immunocytochemistry at the light-microscopic level, using the avidin–biotin complex method, and at the electron-microsopic level, using the protein A – gold method, revealed that rabbit anticarp prolactin, growth hormone, and gonadotropin each reacted with one cell type in an appropriate location in the grass carp pituitary gland. The results of these immunocytochemical studies support the suitability of antibodies raised against common carp hormones in immunocytochemical studies on the grass carp, and, by implication, in radioimmunoassay studies.
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Roksandic, Dragutin, Marija Simic, Anita Radovanovic, and Dusan Gledic. "Body mass, spleen mass and level of thyroid hormones in juvenile hypothyroid rats." Veterinarski glasnik 60, no. 3-4 (2006): 153–62. http://dx.doi.org/10.2298/vetgl0604153r.
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In this paper, the effect of hypothyroidism on body mass and spleen mass of rats was examined during the prenatal and early juvenile periods. Hypothyroidism was induced by the application of propylthiouracil (PTU) in drinking water to the mothers from the first day of gravidity and during lactation, and the offspring were sacrificed on the 14th and 21st days after birth. The body mass of the juvenile rats was measured just before they were sacrificed. The concentrations of triiodothyronine (T3) and thyroxine (T4) in blood serum were determined in control and treated juvenile rats. The results indicate that PTU leads to a reduction in T3 and T4 serum concentrations in treated juvenile rats. Treated juvenile rats had a bigger body mass and spleen mass in comparison with control animals. These data indicate that hypothyroidism induced in the prenatal and early juvenile period leads to an increase in the body mass and spleen mass and disrupts the normal development of the spleen in the course of the examined period. .