The anorexic effect of alpha-melanocyte-stimulating hormone is mediated by corticotrophin-releasing factor in chicks

• Published in: Comparative biochemistry and physiology. Part A, Molecular & integrative physiology Vol. 147; no. 1; pp. 173 - 178
• Main Authors: Tachibana, Tetsuya, Oikawa, Daichi, Takahashi, Hirokazu, Boswell, Tim, Furuse, Mitsuhiro
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.05.2007
• Subjects: Agouti-Related Protein; Alpha-melanocyte-stimulating hormone; alpha-MSH - pharmacology; Animals; Anorexia - chemically induced; Anorexia - metabolism; Chick; Chickens - physiology; Corticosterone; Corticosterone - blood; Corticosterone - secretion; Corticotrophin-releasing factor; Corticotropin-Releasing Hormone - pharmacology; Feeding; Feeding Behavior - drug effects; Humans; Intercellular Signaling Peptides and Proteins - pharmacology; Male; Peptide Fragments - pharmacology; Receptors, Corticotropin-Releasing Hormone - antagonists & inhibitors; Alpha-melanocyte-stimulating hormone; Corticotrophin-releasing factor; Agouti-related protein; Corticosterone; Chick; Feeding
• ISSN: 1095-6433; 1531-4332
• DOI: 10.1016/j.cbpa.2006.12.044

Alpha-melanocyte-stimulating hormone (alpha-MSH) is recognized as an anorexic peptide in the brain of vertebrates, but its mechanism of action has not been identified in birds. Therefore, we investigated whether the anorexic effect of alpha-MSH is mediated by corticotrophin-releasing factor (CRF) in the domestic chick. Firstly, we found that intracerebroventricular (ICV) injection of alpha-MSH dose dependently increased plasma corticosterone (CORT) concentration. This effect was partly attenuated by co-injection of astressin, a CRF receptor antagonist, demonstrating that alpha-MSH stimulated CORT secretion by activating CRF neurons. The alpha-MSH-elicited CORT release was not attenuated by the injection of agouti-related protein, an endogenous melanocortin-4 (MC4) receptor antagonist, suggesting that alpha-MSH stimulated CRF neurons through MC4 receptor-independent pathways. Finally, we found that the anorexic effect of alpha-MSH was partly attenuated by astressin. The present results suggest that the anorexic effect of alpha-MSH in the chick brain is mediated in part by activation of CRF neurons.