The metabolism of progesterone by animal tissues in vitro. 1. Factors influencing the metabolism of progesterone by rat liver and the investigation of the products of metabolism

Abstract

A method is descr. for detn. of small quantities of progesterone in incubated tissue prepns. Application to the study of the in vitro metabolism of progesterone by rat-liver slices and suspensions of disintegrated tissue ("homogenates") has indicated that this tissue contains an enzyme or enzymes which metabolize this steroid. Metabolism is increased by addition of either diphosphopyridine nucleotide or nicotinamide or both, and of citrate to the reaction mixture; it is not inhibited under anaerobic conditions. In a large-scale expt., 28%, of the progesterone incubated with rat-liver "homog-enate" (with added nicotinamide) could be accounted for by isolation of 5 alpha-pregnane-3;20-dione and 5 alpha-pregnan-3 alpha-ol-20-one and of unchanged progesterone.