Temporal effects of infused corticosterone and aldosterone on plasma glucose levels in the American bullfrog (Rana catesbeiana).

The effects of a single infusion of corticosterone or aldosterone on plasma glucose levels were compared in the American bullfrog (Rana catesbeiana). The corticoids were administered, and serial blood samples were collected, via a cannula placed in the common iliac artery. Plasma glucose was estimated by the glucose oxidase method. Plasma glucose levels were essentially unchanged from the time-zero levels at 3 hr after the infusion of 1.0 mg/100 g body wt of corticosterone. The levels subsequently increased to maxima that were approximately 45% greater than the time-zero levels at 9 through 24 hr and then declined to approximately the initial levels by 48 hr after treatment. Infusion of 0.24 mg/100 g body wt of aldosterone did not significantly alter plasma glucose levels. The results suggest that elevated circulating corticosterone is not involved in the primary hyperglycemic response to a stress, but may function synergistically and sequentially with elevated circulating catecholamines in subsequent compensatory adjustments.