Interaction of glucagon and epinephrine in the control of hepatic glucose production in the conscious dog

SM Gustavson, CA Chu, M Nishizawa… - American Journal …, 2003 - journals.physiology.org
SM Gustavson, CA Chu, M Nishizawa, B Farmer, D Neal, Y Yang, EP Donahue, P Flakoll…
American Journal of Physiology-Endocrinology and Metabolism, 2003journals.physiology.org
Epinephrine increases net hepatic glucose output (NHGO) mainly via increased
gluconeogenesis, whereas glucagon increases NHGO mainly via increased glycogenolysis.
The aim of the present study was to determine how the two hormones interact in controlling
glucose production. In 18-h-fasted conscious dogs, a pancreatic clamp initially fixed insulin
and glucagon at basal levels, following which one of four protocols was instituted. In G+ E,
glucagon (1.5 ng· kg− 1· min− 1; portally) and epinephrine (50 ng· kg− 1· min− 1; …
Epinephrine increases net hepatic glucose output (NHGO) mainly via increased gluconeogenesis, whereas glucagon increases NHGO mainly via increased glycogenolysis. The aim of the present study was to determine how the two hormones interact in controlling glucose production. In 18-h-fasted conscious dogs, a pancreatic clamp initially fixed insulin and glucagon at basal levels, following which one of four protocols was instituted. In G + E, glucagon (1.5 ng · kg−1 · min−1; portally) and epinephrine (50 ng · kg−1 · min−1; peripherally) were increased; in G, glucagon was increased alone; in E, epinephrine was increased alone; and in C, neither was increased. In G, E, and C, glucose was infused to match the hyperglycemia seen in G + E (∼250 mg/dl). The areas under the curve for the increase in NHGO, after the change in C was subtracted, were as follows: G = 661 ± 185, E = 424 ± 158, G + E = 1,178 ± 57 mg/kg. Therefore, the overall effects of the two hormones on NHGO were additive. Additionally, glucagon exerted its full glycogenolytic effect, whereas epinephrine exerted its full gluconeogenic effect, such that both processes increased significantly during concurrent hormone administration.
American Physiological Society