Carbohydrate Levels in Fasted and Fed Hypophysectomized Rats. ∗

Abstract

In an inquiry as to the nature of the hypoglycemia and low glycogen stores found in completely hypophysectomized rats, the following experiments have been undertaken: (1) the comparison under standard conditions of the carbohydrate levels of normal, hypophysectomized† and partially hypophysectomized rats when fully fed and when fasted 8 and 18 hours; and (2) the preparation of curves showing the changes in carbohydrate levels in these animals following the feeding of uniform carbohydrate meals.

All rats used were young males 50-70 days of age, the experimental animals 20-30 days post operative. Sodium amytal was used as anesthetic for obtaining samples. Muscle glycogen figures for each animal were the averages of 2 separate determinations, and the liver glycogen values included only fermentable reducing substances. The carbohydrate meals were given in the form of cornstarch, in 50% suspension in water, fed by stomach tube without anesthesia.

It was found that when the hypophysectomized animals were fully fed (taken directly from their cages) all car'bhydrate levels were within normal limits, but that when they were fasted, these levels fell rapidly, as shown in Table I. Each figure in this table represents the decrease in carbohydrate content as per cent of the average levels found in the fully fed animals.