Glucagon and epinephrine suppression of food intake in liver-denervated rats.

Milk intake suppression after intraperitoneal glucagon and epinephrine injections was studied in liver-denervated [hepatic vagal branch transection (VAG-B), hepatic artery-portal vein denervations (H-ART), or total denervation (TOTAL)] and sham-operated rats (SHAM). In experiment 1, glucagon (500 micrograms/kg, Sigma) had no effect on 30 min of milk intake but produced hyperglycemia in all groups. Glucagon (750 micrograms/kg, Sigma; 400 micrograms/kg, Lilly) decreased intake in all groups, as did epinephrine (30 micrograms/kg). In experiment 2, TOTAL and SHAM were tested with 50, 100, and 400 micrograms/kg of glucagon (Lilly). Only the two larger doses suppressed milk intake of both groups, whereas all doses caused hyperglycemia. Epinephrine (30 micrograms/kg) decreased food intake more than glucagon but caused less hyperglycemia than any glucagon dose. In experiment 3, VAG-B and SHAM groups were given glucagon (400 micrograms/kg, Lilly), which reduced their intake. Under these test conditions, liver innervation is not required for glucagon and epinephrine to suppress milk intake. The ability of the two hormones to suppress ingestion appears to be dissociated from their hyperglycemic actions.