Peripheral and central GLP-1 receptor populations mediate the anorectic effects of peripherally administered GLP-1 receptor agonists, liraglutide and exendin-4

SE Kanoski, SM Fortin, M Arnold, HJ Grill… - …, 2011 - academic.oup.com
Endocrinology, 2011academic.oup.com
The long-acting glucagon-like peptide-1 receptor (GLP-1R) agonists, exendin-4 and
liraglutide, suppress food intake and body weight. The mediating site (s) of action for the
anorectic effects produced by peripheral administration of these GLP-1R agonists are not
known. Experiments addressed whether food intake suppression after ip delivery of exendin-
4 and liraglutide is mediated exclusively by peripheral GLP-1R or also involves direct central
nervous system (CNS) GLP-1R activation. Results showed that CNS delivery [third …
The long-acting glucagon-like peptide-1 receptor (GLP-1R) agonists, exendin-4 and liraglutide, suppress food intake and body weight. The mediating site(s) of action for the anorectic effects produced by peripheral administration of these GLP-1R agonists are not known. Experiments addressed whether food intake suppression after ip delivery of exendin-4 and liraglutide is mediated exclusively by peripheral GLP-1R or also involves direct central nervous system (CNS) GLP-1R activation. Results showed that CNS delivery [third intracerebroventricular (3rd ICV)] of the GLP-1R antagonist exendin-(9–39) (100 μg), attenuated the intake suppression by ip liraglutide (10 μg) and exendin-4 (3 μg), particularly at 6 h and 24 h. Control experiments show that these findings appear to be based neither on the GLP-1R antagonist acting as a nonspecific competing orexigenic signal nor on blockade of peripheral GLP-1R via efflux of exendin-(9–39) to the periphery. To assess the contribution of GLP-1R expressed on subdiaphragmatic vagal afferents to the anorectic effects of liraglutide and exendin-4, food intake was compared in rats with complete subdiaphragmatic vagal deafferentation and surgical controls after ip delivery of the agonists. Both liraglutide and exendin-4 suppressed food intake at 3 h, 6 h, and 24 h for controls; for subdiaphragmatic vagal deafferentation rats higher doses of the GLP-1R agonists were needed for significant food intake suppression, which was observed at 6 h and 24 h after liraglutide and at 24 h after exendin-4. Conclusion: Food intake suppression after peripheral administration of exendin-4 and liraglutide is mediated by activation of GLP-1R expressed on vagal afferents as well as direct CNS GLP-1R activation.
Oxford University Press