The action of cortisone on the mammary glands of rats under various states of hormonal imbalance.

Abstract

Summary. The action exerted by cortisone on the mammary glands of castrated female rats was studied under various endocrine conditions. The main results were as follows: A) Pituitary gland removed: 1 Cortisone promoted enlargement and proliferation of the epithelial cells lining the inner walls of the ducts. Normal growth and differentiation did not occur. 2 The effect of cortisone + oestrone and progesterone was roughly the same as in “1)”. 3 The growth of normal structures occurring after treatment with oestrone, progesterone + long-acting insulin was markedly reduced by cortisone. The effect on the duct epithelium described under “1)” predominated. B) Pituitary gland intact: 1 Cortisone stimulated secretion, but not growth. After prolonged treatment the duct epithelium appeared enlarged, but did not proliferate. 2 Cortisone + oestrone and progesterone promoted growth and abundant secretion. The development of acini appeared enhanced by the addition of cortisone to the ovarian steroids. Abnormalities of duct epithelium were not found. 3 The result obtained after treatment with cortisone, oestrone, progesterone + long-acting insulin was similar to that of “2)”, but secretion appeared more abundant. 4 The observations made on a total of seven groups of rats subjected to different treatments are summarized and discussed with regard to the dependence of the mammary gland response to cortisone upon the endocrine balance both as to effects on mammary gland structures and the general metabolism.