Ghrelin is an endogenous ligand for the growth hormone secretagogue (GHS) receptor. Ghrelin stimulates feeding in rats, however, intracerebroventricular (i.c.v.) injection of rat ghrelin inhibits feeding of neonatal chicks. In the present study, the effect of i.c.v. injection of different ghrelins including chicken and bullfrog ghrelin, and synthetic GH-releasing peptide (GHRP) on feeding of neonatal chicks was investigated. Chicken ghrelin strongly suppressed feeding. To compare the inhibitory effect, chicken and rat ghrelin were examined. The suppressive effect of feeding by chicken and rat ghrelin was almost identical. Bullfrog ghrelin contains a change in the acylated amino acid from Ser to Thr, strongly suppressed feeding. The i.c.v. injection of GHRP-2 (KP-102), a synthetic GHS, also inhibited feeding. These results indicate that the chicken GHS receptor is affected by several forms of GHS, and that food intake of neonatal chicks is inhibited by GHS receptor agonists.
Copyright 2002 Elsevier Science B.V.