Melatonin Modulates Secretion of Growth Hormone and Prolactin by Trout Pituitary Glands and Cells in Culture
Jack Falcón,Laurence Besseau,D. Fazzari,Joël Attia,Pascaline Gaildrat,Marilyn Beauchaud,Gilles Boeuf +6 more
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TLDR
It is shown that 2-[125I]-iodomelatonin, a melatonin analog, binds selectively to membrane preparations and tissue sections from trout pituitaries, providing the first evidence that melatonin modulates GH and PRL secretion in Teleost fish pituitary.Abstract:
In Teleost fish, development, growth, and reproduction are influenced by the daily and seasonal variations of photoperiod and temperature. Early in vivo studies indicated the pineal gland mediates the effects of these external factors, most probably through the rhythmic production of melatonin. The present investigation was aimed at determining whether melatonin acts directly on the pituitary to control GH and prolactin (PRL) secretion in rainbow trout. We show that 2-[125I]-iodomelatonin, a melatonin analog, binds selectively to membrane preparations and tissue sections from trout pituitaries. The affinity was within the range of that found for the binding to brain microsomal preparations, but the number of binding sites was 20-fold less than in the brain. In culture, melatonin inhibited pituitary cAMP accumulation induced by forskolin, the adenyl cyclase stimulator. Forskolin also induced an increase in GH release, which was reduced in the presence of picomolar concentrations of melatonin. At higher con...read more
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Current knowledge on the melatonin system in teleost fish
TL;DR: How manipulation of the photic cues impact on fish circannual clock and annual cycle of reproduction, and how this can be used for aquaculture purposes is discussed.
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Melatonin effects on the hypothalamo–pituitary axis in fish
TL;DR: Studies of the targets and modes of action of melatonin in fish, and their parallels in mammals, are of interest to the understanding of time-related neuroendocrine regulation and its evolution from fish to mammals, as well as for aquacultural purposes.
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Neuroendocrine control of growth hormone in fish.
TL;DR: Results from investigations on a limited number of stimulatory and inhibitory GH-release regulators indicate that activation of different but convergent intrACEllular pathways and the utilization of specific intracellular Ca(2+) stores are some of the strategies utilized.
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Osmotic stress sensing and signaling in fishes.
TL;DR: Overall, current insight into osmosensing and osmotic stress‐induced signal transduction in fishes is limited, however, euryhaline fish species represent excellent models for answering critical emerging questions in this field and for elucidating the underlying molecular mechanisms of Osmosensory signal Transduction.
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Melatonin activates brain dopaminergic systems in the eel with an inhibitory impact on reproductive function.
Marie-Emilie Sébert,C. Legros,Finn-Arne Weltzien,Finn-Arne Weltzien,Benoît Malpaux,Philippe Chemineau,Sylvie Dufour +6 more
TL;DR: The results of the present study provide the first evidence that melatonin enhances TH expression in specific brain regions in a non‐mammalian species, and could represent one pathway by which environmental factors could modulate reproductive function in the eel.
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How should salinity influence fish growth
Gilles Bœuf,Patrick Payan +1 more
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Endocrine control of osmoregulation in teleost fish
TL;DR: Current understanding indicates that growth hormone promotes acclimation to seawater, prolactin promotes acclamation to fresh water, and cortisol interacts with both of these hormones thus having a dual osmoregulatory function.
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Does light have an influence on fish growth
TL;DR: A review of the present knowledge on the involvement of light influence on hormone levels (melatonin, somatotropin, thyroid hormones and other hormones) and a discussion about the endolymph–otolith system, which is very sensitive to daylight and seasonal cycles.