Rat ghrelin stimulates growth hormone and prolactin release in the tilapia, Oreochromis mossambicus.
Recently, ghrelin (Ghr), a new peptide which specifically stimulates growth hormone (GH) release from the pituitary, was identified in the rat and human stomach. Ghrelin has been shown to stimulate GH release by acting through a growth hormone secretagogue (GHS) receptor in the rat. The present study describes the in vitro effect of rat Ghr on the release of GH and two forms of prolactin (PRL(177) and PRL(188)) in the tilapia, Oreochromis mossambicus. Rat Ghr stimulated the release of GH in a dose-related manner after 8 and 24 hr of incubation. Rat Ghr also significantly stimulated the release of PRL(177) and PRL(188) in a dose-related manner after 24 hr. Rat Ghr had no effect on the pituitary content of GH or PRL(188), but significantly increased PRL(177) content. These results show for the first time that rat Ghr significantly stimulates GH and PRL release in teleosts, and suggest that Ghr and a GHS receptor are present in fish.
Riley
Larry G
LG
Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe 96744, USA.
Hirano
Tetsuya
T
Grau
E Gordon
EG
D000818:Animals; D004305:Dose-Response Relationship, Drug; D054439:Ghrelin; D013006:Growth Hormone / Q000378:metabolism*; D036361:Peptide Hormones / Q000494:pharmacology*; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism; D011388:Prolactin / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism; D017210:Tilapia / Q000378:metabolism*
D054439:Ghrelin; D036361:Peptide Hormones; D011956:Receptors, Cell Surface; D011388:Prolactin; D013006:Growth Hormone