Effect of Extract of Adrenal Cortex upon Thymic Weight and Resistance to Bacterial Intoxication in Chronic Adrenal Insufficiency.

Abstract

Extirpation of both adrenal glands is rapidly fatal in most laboratory animals. However this operation seems to have little effect for several weeks upon the physical condition of the majority of rats submitted to it. But such apparently healthy survivors manifest at least 2 important differences from normal rats, an increased susceptibility to bacterial intoxication, 1 and hypertrophy of the thymus. 2 In each instance the variation has been correlated with a functional deficiency of the adrenal cortex rather than of the medulla.

It is our purpose to report the effect of an extract of the adrenal cortex upon this chronic type of adrenal insufficiency, using as criteria the resistance of the animals to bacterial intoxication and the size of the thymus.

Fifty-eight rats from 5 litters born on the same day were used. These were divided into 3 groups and sampled for the different groups according to the method adopted by Dr. Luce Clausen, 3 insuring equal distribution of weight and equal representation of the different litters in each group. At the beginning of the experiment the mean actual weights of the 3 groups were as follows:

Each of the first 2 groups contained 19 members. Group 3 was used for control determinations of body weight and thymus weight and was subdivided into 2 similar parts of 10 members each, one of which (A) received the injection of typhoid vaccine and the other (B) did not. All members of Groups 1 and 2 were doubly adrenalectomized on the same day and were injected subcutaneously with 1/2 cc. of fluid twice daily for 2 weeks after operation. Group 2 received an extract of the adrenal cortex made and kindly supplied to us by Drs. W. W. Swingle and J. J. Pfiffner, 4 while in Group 1 the same amount of Ringer's solution was used.