<b>EFFECT OF GLUCAGON-LIKE PEPTIDE-1 AND -2 ON GLYCOGENOLYSIS IN CULTURED RAT </b><b>HEPATOCYTES </b>

Abstract

Glucagon-like peptides, GLP-1 and GLP-2, show high conservation in different species and substantial sequence homology of glucagon. GLP-1 and GLP-2 have no effect on glycogenolysis, at least in part, directly in hepatocytes, in contrast to glucagon which caused marked stimulation of cAMP formation, glycogen phosphorylase a activity and glucose release in cultured rat hepatocytes. Furthermore, rat liver membranes do not exhibit specific binding of radiolabeled GLP-1, while GLP-1 has its own receptors in rat pituitary membranes. The presence of specific, high-affinity receptors for GLP-1 was confirmed by demonstrating that GLP-1 stimulated cAMP formation in the pituitary gland. These findings suggest that GLP-1 may not act on liver but act on brain and play a role in the central nervous system.