Effect of Cortical Extract on Glucose Tolerance of Adrenalectomized and Hypophysectomized Rats

Abstract

In previous work 1 we found that the ability of the hypophysectomized rat to remove excess sugar from the blood stream decreased with time after operation. This gradual decrease in ability to remove excess sugar indicated that the effect must be due to the progressive atrophy or derangement of some other organ following removal of the pituitary body. We gave our first attention to the rôle of the adrenal gland in this effect since Leloir 2 had shown a decrease in the rate of removal of glucose from the blood in adrenalectomized dogs, associated with decreased glycogen formation.

To test this possible connection the following groups of male rats were given 0.125 gm. glucose per 100 gm. body weight by injection of 50% solution into the saphenous vein:

a. Normal control animals.

b. Normal animals injected with 0.2 cc. Wilson's adrenal cortex extract per day.

c. Young adult animals adrenalectomized 6 days previously.

d. Similar adrenalectomized animals injected with 0.2 cc. extract per day for the previous 4 days.

e. Hypophysectomized animals, operated on 17 days previously.

f. Similar hypophysectomized animals injected with 0.2 cc. extract per day for the previous 6 days.

All animals were fasted for 24 hours before receiving the glucose injections. Blood sugar samples were taken from the tail vein, the first few drops being discarded. Samples were taken fasting and at 10, 20, 30, 60, and 120 minutes after injection. Table I gives the average values for the various groups.

The defect in ability to remove excess sugar from ithe ldooci in the hypophysectoniizecl iiiale rat is not relieved by cortical extract, while that observed in the atlrenalectornized animal disappears. It seem then that the deficiency brought on by renioval of the pituitary glaiitl is not solely, ii at all. a result of atrophy of the adrenal cortex. Since the normal rats injected with cortical extract showed no greater rate of g-lucose removal than the uninjected controls. the action of the cortical extract in adrenalectoniized rats on the tolerance must be due to its specific action in relieving cortical insufficiency.