Comparison of Glucagon and Epinephrine Effects in the Dog

Intravenous injection of 1–2 μg/kg of glucagon produced greater and more persistent effects on liver glycogen and blood glucose of dogs than 10–50 μg/kg of epinephrine. When administration was by portal vein infusion, glucagon appeared to be more than 100 times as potent a glycogenolytic agent as epinephrine. Epinephrine produced greater effects via the femoral vein than when infused into the portal vein; It is concluded that in the dog, as well as in the rat, only glucagon can serve as a physiologic hepatic glycogenolytic agent, and that the effect of moderate doses of epinephrine on the liver is an indirect one, possibly mediated through stimulation of glucagon secretion. (Endocrinology78: 47, 1966)