Inactivation of Progesterone in the Organism

Abstract

SOME years ago, I was able to demonstrate that œstrone which had been administered to the organism very soon became inactive¹. Mature mice or infantile rats were injected subcutaneously with large doses of œstrone (up to 40,000 M.U.). Three to seventy-two hours after the administration of the hormone the animals were killed, cut into small pieces and extracted in toto with an organic solvent. It was apparent that even after a very short time, only very insignificant amounts of the hormone (about 1 per cent) could be detected. There remained, indeed, always a certain quantity of active hormone, sufficient to produce œstrus; but the question whether we were considering a hormone which had not become inactive, or one which had become reactivated again, could not be decided. œstrone is inactivated in the liver, probably by means of an enzymatic process. This inactivation, apparently, is a general biological reaction, since it takes place not only in warm-blooded, but also in cold-blooded animals and in plants as well.