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Gh important for seawater adaptation in coho salmon

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Unformatted text preview: (prob synergy) in terms of effects on growth, as in mammals •  GH induces IGF-1 in salmon and other fishes. •  GH important for seawater adaptation in Coho salmon: GH increase here does not cause IGF-1 and growth increase Salmon life-cycle 4 3/15/13 PRL, GH and SL in Bony Fishes •  SL is the most recent hormone to be identified in the pituitary polypeptide family •  Histological clues were provided by a novel type of cell in teleost pars intermedia. These stained with periodic acid-Schiff (PAS) reagent – hence “PIPAS” cells. These cells are sensitive to calcium in their immediate environment. •  Salmonids lack PIPAS cells, but have SL immunopositive cells in the pars intermedia. •  SL important for calcium balance, pigmentation, reproduction, metabolism of phosphate and lipid. Smoltification and gonadal maturation are correlated with high SL. •  Two subfamilies of SL: Slα and SLβ SL and pigmentation 5 3/15/13 PRL and GH in Amphibians •  PRL may act as GH in larval amphibians •  Even though PRL influences larval growth, it is anti-metamorphic in anurans and caudate amphibians. •  PRL induces water-driven behavior in newts and salamanders, along with secondary sexual characters (red eft behavior) •  Eft video 6 3/15/13 PRL and GH in Amphibians •  Confusing, as PRL might be the larval form of GH •  GH might only operate in metamorphosed animals •  Frog GH and mammalian GH are very similar in structure and physical properties, suggesting that GH is highly conserved during evolution of the tetrapods. •  However, frog GH not as effective as bovine GH in rat tibia bioassay •  IGF has been seen in toads, but no link to GH or PRL known as yet. Not well-studied. 7...
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