Distribution of Enzyme Systems Responsible for Steroid Metabolism in Different Tissues and Subcellular Fractions

Abstract

FROM their studies of the in vivo metabolism of various biologically active and inactive 11-oxygenated steroids, Bush and Mahesh¹ believe that the glucocorticoid activity of these steroids is due to the specific interaction of an llβ-hydroxy group on the steroid molecule with the receptor sites for such hormones, and that such an interaction does not involve oxidation-reduction at C–11. However, Talalay and co-workers² observed that various hydroxy-steroids, including the 11-oxygenated ones, can act as coenzymes in the transfer of hydrogen between pyridine nucleotides in the presence of suitable steroid dehydrogenases and they suggest that this is the mode of action of steroid hormones. In the present study, the metabolism of cortisol and cortisone has been investigated in various tissues in order to determine the distribution of enzyme systems responsible for the metabolism of the steroids, with the view of finding out whether steroid metabolism is directly involved in hormone action or whether it represents stages in their detoxication and removal from the body.