INHIBITION OF PROGESTERONE IN DECIDUAL DEVELOPMENT BY STEROID COMPOUNDS12

Abstract
THE inhibition of progesterone by estrogens has been reported by many investigators and the literature dealing with this reaction has been reviewed by Courrier (1950). More recently, we (Velardo and Hisaw, 1951) have made a comparative study of the inhibitory action of several estrogens on the decidual response in rats, and also have extended our observations to include other steroid compounds. We were interested particularly in natural and synthetic compounds that are more or less chemically related to progesterone and which are non-progestational in their action or are effective only at high doses. It was thought that certain of the inactive steroids might compete with progesterone and thus modify the development of deciduomata. The present paper reports the results of a series of experiments designed to test this possibility.