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The upstream migration of adult anadromous fishes is characterized by physiological changes in responses to reproductive and
energetic challenges. This study analyzed the physiological responses of lake-resident anadromous masu salmon (Oncorhynchus masou) and sockeye salmon (O. nerka) to migration in order to determine if these fish might serve as a suitable model for ocean-running populations and to differentiate
between physiological responses to reproduction and to exercise-linked aspects of migration. Reproductive (estradiol, testosterone,
11-ketotestosterone, 17α,20β-dihydroxy-4-pregnen-3-one) and metabolically-linked (thyroxine, triiodothyronine) hormones showed
similar patterns to ocean-running anadromous populations. White muscle pyruvate kinase, lactate dehydrogenase and malate dehydrogenase
decreased with the onset of spawning season while white muscle citrate synthase, β-hydroxyacetyl CoA dehydrogenase, phosphofructokinase
and glutamate oxaloacetate transaminase did not, suggesting that the former group of enzymes are responding to reproductive
or food intake signals while the second group, which typically change during anadromous migration, may be responding to exercise-linked
aspects of migration.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
3.
Reproduction in fishes is influenced by thyroid hormones at various levels of gonadal cell differentiation and steroidogenesis.
Thyroid hormones have recently also emerged as an important modulator of season- and photoperiod-dependent variations in the
reproductive cycle with a possible effect on the hypothalamo–hypophyseal axis and pineal interactions. This review describes
the current status of thyroid hormone research in relation to reproduction, with special emphasis on contributions to this
field by Indian researchers including our laboratory. Evidence is provided for the multifocal action of thyroid hormones at
various levels of the hypothalamo–hypophyseal–gonadal axis affecting reproduction. The underlying physiological and molecular
mechanisms pertaining to thyroid hormone modulation of reproduction, such as gonadotropin-releasing hormone (GnRH) synthesis
and release, androgen and gonadotropin receptor expression, gonadotropin (GTH) expression, and tissue sensitivity to GTHs
are highlighted with relevant discussions of the current technical limitations, applications, and future perspectives of research
in this field. 相似文献
4.
Thyroid hormone‐induced swim bladder and eye maturation are transduced by IGF‐1 in zebrafish embryos
Mohammad Habibur Rahman Molla Md T. Hasan Won J. Jang Cesar D. Soria Diaz Patrick Appenteng Haliliy Marufchoni Bushra Jahan Christopher L. Brown 《Aquaculture Research》2019,50(11):3462-3470
Maternally derived thyroid hormones (THs) deposited in yolk promote fish embryogenesis and survival, and understanding early regulatory mechanisms could lead to improved seedstock production. We have tested the hypothesis that some thyroid actions may be mediated by insulin‐like growth factor I (IGF‐1), another promoter of embryo development. Differentiation and performance were assessed in embryos treated with THs in the presence or absence of an IGF‐1 receptor blocking peptide. Treatment with the TH triiodothyronine (T3) promoted IGF‐1 gene expression at days 1 and 5, and advanced swim bladder and eye development, but blocking the IGF‐1 receptor eliminated the swim bladder and eye effects. Growth and survival at 1 week of age were impaired by the IGF‐1 receptor blocking peptide alone, but concurrent treatment with T3 partially restored these indices. Our results confirm interaction of T3 and IGF‐1 regulatory signalling in zebrafish embryogenesis and transduction by IGF‐1 of thyroid‐driven swim bladder and eye maturation. 相似文献
5.
Osmoregulatory actions of growth hormone and its mode of action in salmonids: A review 总被引:8,自引:0,他引:8
Tatsuya Sakamoto Stephen D. McCormick Tetsuya Hirano 《Fish physiology and biochemistry》1993,11(1-6):155-164
Osmoregulatory actions of growth hormone (GH) and its mode of action in salmonids are reviewed. We present evidence suggesting
that insulin-like growth factor I (IGF-I) mediates some of the actions of GH on seawater acclimation. Plasma concentration
and turnover of GH rise following exposure to seawater. Exogenous GH (in vivo) increases gill Na+,K+-ATPase activity and the number of gill chloride cells, and inhibits an increase in plasma osmolarity and ions following transfer
of fish to seawater. A single class of high affinity GH receptors is present in the liver, gill, intestine, and kidney. The
levels of IGF-I mRNA in the liver, gill and kidney increased after GH-injection. After transfer to seawater, IGF-I mRNA increased
in the gill and kidney following the rise in plasma GH, although no significant change was seen in the liver. Injection of
IGF-I improved the ability of the fish to maintain plasma sodium levels after transfer to seawater. GH treatment also sensitizes
the interrenal to adrenocorticotropin (ACTH), increasing cortisol secretion. Both cortisol and IGF-I may be involved in mediating
the action of GH in seawater adaptation, although studies on the effect of GH on osmoregulatory physiology of non-salmonid
species are limited. An integrated model of the osmoregulatory actions of GH is presented, and areas in need of research are
outlined.
Résumé Cet article est une revue des effets osmorégulateurs de l'hormone de croissance et de son mode d'action. Nous présentons des résultats qui suggèrent que le facteur de croissance de type insuline (IGF-I) est un médiateur de certaines des actions de la GH sur l'adaptation à l'eau de mer. Les concentrations plasmatiques et le renouvellement de la GH augmentent après transfert en eau de mer. La GH exogène stimule (in vivo) l'activité Na+,K+-ATPase et le nombre de cellules à chlorure branchialeset inhibe les augmentations de l'osmolarité et des concentrations ioniques du plasma observées après transfert en eau de mer. Une seule classe de récepteurs à haute affinité pour la GH est présent dans le foie, les branchies, l'intestin et le rein. Les niveaux d'ARNm d'IGF dans le foie, les branchies et le rein augmentent après injection de la GH. Après transfert en eau de mer, les ARNm de l'IGF augmentent dans les branchies et dans le rein en suivant l'augmentation de GH plasmatique, bien qu'aucune modification ne soit observée au niveau du foie. L'injection d'IGF augmente la capacité du poisson à maintenir ses niveaux de sodium plasmatique après transfert en eau de mer. Le traitement à la GH augmente la sensibilité à l'adrenocorticotropine (ACTH) et stimule donc les niveaux de cortisol. A la fois le cortisol et l'IGF-I semblent impliqués comme médiateurs des effets de la GH dans l'adaptation à l'eau de mer, bien que les études sur les effets de la GH sur la physiologie de l'osmorégulation chez les espèces non-salmonidés restent encore limitées. Un modèle intégré des actions de la GH sur l'osmorégulation est présenté et les domaines de recherche à développer sont soulignés.相似文献
6.
The diurnal rhythms of plasma glucose, cortisol, growth hormone (GH) and thyroid hormone (T4, T3) concentrations and hepatic glycogen content were measured in rainbow trout that had been entrained to a specific time of
daily feeding (post-dawn, midday, pre-dusk); the purpose of the study was to investigate the significance of feeding time
on hormones and metabolite patterns. Plasma GH, cortisol and T4 concentrations all showed evidence of a diurnal rhythm in some treatment groups. There was a significant interaction between
the time of feeding and plasma GH and cortisol concentration rhythms; for GH, this appeared to be related to the phase-shifting
of the post-prandial increases in plasma GH concentrations, and for cortisol, the rhythms were only evident in fish fed in
the post-dawn period [diurnal rhythms were not evident in treatment groups fed in at midday or pre-dusk]. Peak plasma T4 concentrations were evident during the photophase in all three treatment groups; however, the time of feeding had a negligible
effect on the timing of those peaks. There were no apparent diurnal rhythms of plasma T3 and glucose concentrations, hepatic glycogen content or hepatosomatic index in any of the three treatment groups.
To whom correspondence should be addressed 相似文献