An Apparent Sex-Specificity in the Action of Progesterone on Adrenalectomized Cats

Stewart 1 first called attention to what he considered an unusual prolongation of the life-span of pregnant cats following adrenal removal. Later, Stewart and Rogoff, 2 working with dogs, reported similar findings and suggested the corpus luteum as the life-maintaining tissue in such animals. The writer 3 was subsequently unable to substantiate these claims in a study of an extended series of pregnant and lactating cats. Recent reports of prolonged survival in adrenalectomized pseudopregnant dogs 4 5 rats, 6 , 7 and ferrets, 8 9 together with the availability of progesterone in synthetic form, have led to a revival of interest in this phase of adrenal physiology.

Eight female and 2 male cats were adrenalectomized, and injections of progesterone (“Proluton”∗) were begun at the first appearance of definite symptoms of cortico-adrenal insufficiency (anorexia, weakness, uncertain gait). The concentration of the blood glucose was followed throughout all experiments, and terminal determinations of the serum sodium, chloride, potassium and urea were made, as well as liver, muscle and cardiac glycogen.

The results obtained from the injection of progesterone into male animals indicated that the hormone served as an adequate replacement therapy in the absence of the adrenal cortex. Particularly notable was the restoration of normal carbohydrate levels following post-adrenalectomy depletion. The recovery of male cats from definite symptoms of cortical insufficiency was rapid, and similar to that seen in cats treated with cortico-adrenal extract. The blood chemistry at this time was found to be essentially normal. The injection of progesterone was stopped 21 days after operation when both animals were in excellent condition. They subsequently succumbed, with typical symptoms of adrenal insufficiency and careful examination failed to reveal any trace of adrenal tissue.