Abstract

During exercise, the liver has the predominating role of providing glucose by glycogenolysis or gluconeogenesis for oxidation by the brain and working muscles. The rate of liver glycogenolysis increases during exercise and the magnitude of the increase is dependent on work rate. Several hormonal and neuroendocrine systems exist which may play a role in governing the liver glycogenolytic rate during exercise. These include the effects of glucagon, humoral epinephrine and norepinephrine, norepinephrine released by sympathetic nerves adjacent to hepatocytes, VIP vasopressin, and angiotensin II. Despite the large amount of in vitro data on the mechanisms of each of these hormones, the relative role of each system in governing the rate of glycogenolysis during exercise is unclear. Verf.-Referat