Glycogen stores in glucagon-treated rats. I. Time factors.

Abstract

1. Effects of epinephrine and various doses of glucagon on liver and muscle glycogen and on adrenal ascorbic acid were studied. 2. Twenty minutes after injection of epinephrine a decrease in liver and muscle glycogen, and in adrenal ascorbic acid were observed. Two hours after injection, liver glycogen was significantly higher than in controls, while muscle glycogen and adrenal ascorbic acid were still below normal. 3. Glucagon caused immediate decrease in liver glycogen. When large doses were used this decrease was followed by secondary increase to values greater than normal. 4. The glycostatic effect of large doses of glucagon in the liver was probably associated with an earlier decrease in adrenal ascorbic acid. 5. Glucagon caused an occasional slight increase of muscle glycogen. 6. It is suggested that the primary effect of epinephrine and of glucagon in all doses is an acceleration of liver glycogenosis and that their glycostatic effects are due to secondary increases in secretion of insulin and/or adrenal cortical hormones.