Effects of Hormones on Carbohydrate Metabolism in the Alligator

Abstract

The use of cold-blooded animals in research on carbohydrate metabolism permits one to observe the effects of stimuli for a period of days instead of minutes. With this fact in mind, epinephrine, insulin, hydrocortisone, glucagon and purified bovine somatotropin were injected into young alligators for various periods of time. Following the injections, bloods and urines were analyzed for glucose, lactate and electrolytes. Epinephrine and glucagon produced a 250–400 mg % rise in blood glucose. This hyperglycemia lasted for as long as 70 hours. Whereas epinephrine evoked a marked hyperlactemia which lasted for 10–20 hours, glucagon had no effect on lactic acid. Alligators primed with hydrocortisone showed a decreased ability to dispose of the lactic acid produced by epinephrine. Although epinephrine quickly reduced the stores of liver and muscle glycogen, the glycogen supply was replenished in 5 days or less, even when the alligators were deprived of food. Both somatotropin and hydrocortisone produced a slight hyperglycemia when given singly. When combined, they caused a marked hyperglycemia with glycosuria. In spite of the production of an apparent ‘diabetes,’ these alligators disposed of exogenous glucose at a nearly normal rate.