Glycogen stores in glucagon-treated rats. II. Effect of alloxan diabetes.

Abstract

1) The effects of glucagon and of epinephrine on liver and muscle glycogen and adrenal ascorbic acid of alloxan diabetic rats were studied. 2) Twenty minutes after injection of epinephrine a decrease in liver and muscle glycogen was observed. The decrease was still greater after 2 hours. 3) Two hours after injection of glucagon there was a decrease in liver glycogen and, in one experiment, an increase in muscle glycogen. 4) Twenty-four hours after injection of glucagon, liver glycogen had returned to, but not above, the initial level. 5) The adrenal glands of alloxan diabetic rats are significantly larger than those of normal rats. The injection of glucagon or epinephrine may further stimulate adrenal cortices, as indicated by occasional decrease in their ascorbic acid content. 6) It is concluded that: a) the glycogenolytic effects of glucagon and epinephrine are unimpaired in alloxan diabetes, and b) the delayed increase in liver glycogen, observed in normal rats after injection of epinephrine or glucagon, requires the presence of an intact insulin-secreting system capable of being stimulated by epinephrine or glucagon hyperglycemia.