Recent Studies have demonstrated that glucagon-like peptide-1 (GLP)(7-37) has more potent insulinotropic activity than glucagon. We therefore examined the effect of GLP-1(7-37) on liver metabolism using rat liver perfusion system. Ten nM GLP-1(7-37) did not affect glucose, ketone body and cAMP outputs from the perfused liver. Whereas, the same dose of glucagon stimulated these outputs significantly. When 10 nM GLP-1(7-37) perfused 5 min before the administration of 10 nM glucagon, the above stimulatory effects of glucagon were not affected. These results indicate that truncated GLP-1 has no effect on hepatic glycogenolysis and ketogenesis dissociating from its potent insulinotropic activity.