Intracerebroventricular injection of ghrelin and growth hormone releasing factor inhibits food intake in neonatal chicks.
Growth hormone releasing factor (GRF) is known to stimulate feeding of rats. Ghrelin, a novel growth hormone (GH)-releasing acylated peptide, was recently isolated from rat stomach. It also stimulates the release of GH from the anterior pituitary through the GH secretagogue receptor (GHS-R) and feeding in the rat. We have investigated the effects of ghrelin and GRF on food intake of the neonatal chick. In Experiment 1, 0, 1.25, 2.5 and 5 microg of ghrelin were administered intracerebroventricularly (i.c.v.) to ad libitum fed birds. In Experiment 2, the effect of (i.c.v.) injection of 0, 1.25, 2.5 and 5 microg of GRF was investigated. Both peptides strongly inhibited food intake of the chick during the 2-h post-injection period. In the third experiment, 0, 0.5, 1 and 2 microg of ghrelin was injected i.c.v. in chicks previously deprived of food for 3 h. Food intake was again inhibited by ghrelin in a dose-dependent manner. These results suggest that the mechanisms for feeding of the neonatal chick through GH release are different from mammals.
Laboratory of Advanced Animal and Marine Bioresources, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 812-8581, Fukuoka, Japan. furuse@agr.kyushu-u.ac.jp
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D000367:Age Factors; D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens; D004435:Eating / Q000187:drug effects*; D054439:Ghrelin; D013007:Growth Hormone-Releasing Hormone / Q000737:chemistry / Q000494:pharmacology*; D007276:Injections, Intraventricular; D008297:Male; D008969:Molecular Sequence Data; D036361:Peptide Hormones; D010455:Peptides / Q000494:pharmacology*; D010903:Pituitary Gland, Anterior / Q000502:physiology
D054439:Ghrelin; D036361:Peptide Hormones; D010455:Peptides; D013007:Growth Hormone-Releasing Hormone