Effect of Stimulation of Endogenous Glucagon Secretion by Amino Acid Administration on Canine Hepatic Bile Flow

Exogenous glucagon administration is associated with stimulation of hepatic bile flow. The physiologic role that glucagon plays in the control of hepatic bile flow remains indeterminant. The purpose of this study was to evaluate amino acid administration, a stimulus of endogenous glucagon release, on canine hepatic bile flow. The experiments were performed utilizing cholecystectomized dogs with chronic biliary fistulas. The enterohepatic circulation of bile salts was artificially maintained by intravenous bile salt administration. Intravenous L-arginine stimulated endogenous glucagon release and hepatic bile secretion. Intravenous amino acid administration produced significant increases in hepatic bile flow and plasma glucagon and was significantly more potent than intravenous arginine. Intravenous amino acid administration produced small but significant increases in serum insulin but did not significantly change plasma concentrations of cholecystokinin. The results of this study suggest that endogenous glucagon secretion produces a choleresis and supports a role for glucagon in the physiologic control of canine hepatic bile flow.