Peripheral ghrelin inhibits feed intake through hypothalamo-pituitary- adrenal axis-dependent mechanism in chicken

Abstract

It is known that centrally injected ghrelin is an anorexigenic peptide in chicken. Its activity is not mediated by NPY/AgRP - producing neurons but through the corticosterone releasing hormone (CRH) - expressing neurons in hypothalamus which activate the hypothalamo-pituitary-adrenal (HPA) axis inducing an increase in plasma corticosterone levels. However, controversial results of peripheral ghrelin effect on appetite have been reported. Thus, the influence of intraperitoneal-injected ghrelin on the activity of the HPA axis in Cobb broiler chickens was examined. In addition, the effect of glucocorticoids antagonist (RU486) on the ghrelin activity was also investigated. The intraperitoneal co-injection of CRH-receptor antagonist, astressin, partially attenuated ghrelin-induced anorexia and corticosterone release. Co-administration of RU486 significantly enhanced the inhibitory effect of ghrelin on feed intake in 7-day- old broiler chickens. These results indicate that the peripheral ghrelin - induced anorexia is caused by the stimulation of HPA axis in chickens.