Effects of Administration of Cortin to the Hypophysectomized Rat. ∗

Abstract

Among the results of experimental hypophysectomy in mammals are loss of weight, or, in young animals, failure to increase in weight, loss of libido sexualis, cessation of estrus, or sexual infantilism, lessened spontaneous activity, lowered metabolism and lowered temperature. 1 , 2 , 3 Autopsy of such animals shows atrophy of the thyroid, the adrenal cortex, the gonads, the secondary sex organs, and the thymus. It is apparent that the hypophysectomized animal is characterized not only by absence of the pituitary but also by a marked reduction in size, and presumably also in function, of several other highly important endocrine glands. Considerable light has been thrown on the respective rôles of the thyroid and the gonads in this complex endocrine disturbance. 2 , 4 The functional relationships of the adrenal cortex in the above pictured syndrome are not so well known; what symptoms and what glandular deficiencies. if any, are secondary to the atrophy of this important endocrine gland following removal of the pituitary?

We have previously reported the results of cortin treatment in hypophysectomized Amphibia. 5 In our mammalian experiments albino rats weighing from 150-200 gm., principally from the Wistar experimental colony strain were used. Beginning about the 6th day following hypophysectomy certain animals received daily two 0.5 cc. injections of cortin. Other operated animals were injected at similar times with an equal amount of salt solution. Still other litter mates, unoperated, were available for controls. The operated animals were weighed and daily vaginal smears obtained from the females. In the latter part of the experiment spontaneous activity cages, which recorded revolutions, were available and some of the animals lived in them. The rats were killed from 4 to 8 weeks following operation after having received treatment for from 3 to 7 weeks.