Glucagon-like Peptide-2 Functions as an Anorexigenic Peptide not only in the Central Nervous System but also in the Peripheral Circulation in Broiler Chicks

Brain-gut peptides play important roles in the appetite regulatory system in mammals. Glucagon-like peptide (GLP)-1, GLP-2, and oxyntomodulin (OXM) are processed from the same precursor, proglucagon, in both brain and intestines in mammals and birds. We previously showed that intracerebroventricular administration of these three peptides significantly suppressed food intake in chicks. However, peripheral roles of chicken GLP-2 have not yet been investigated, although GLP-2 plays important roles both in central and peripheral regulation of food intake in mammals. The aim of this study is to investigate whether GLP-2 functions as an anorexigenic peptide in both brain and peripheral circulation in chicks. Intracerebroventricular administration of GLP-2 significantly suppressed food intake in chicks. Twenty-four hours of fasting significantly decreased the mRNA level of proglucagon in the medulla oblongata of chicks. These results suggest that GLP-2 functions as anorexigenic peptides in the central nervous system in chicks. In addition, intravenous administration of GLP-2 significantly suppressed food intake in chicks. Lines of evidence suggest that dietary nutrients stimulate the secretion of GLP-2 from L cells in the small intestine in chickens. These findings suggest that GLP-2 functions as both central and peripheral anorexigenic signals in chicks.