The conversion of testosterone-3-C14 to C14-estradiol-17beta by human ovarian tissue.

There is a considerable body of biological data linking testosterone and other 19-carbon steroids with the estrogens. Both ovaries and testes may, under certain circumstances, produce androgens and estrogens (14). The administration of testosterone and other androgens to human subjects leads to an increased urinary excretion of estrogenic material (5-lo), which has been identified as estrone, estradiol, and estriol (11). These observations suggest a possible conversion of 19-carbon steroids to phenolic estrogens. Studies on the biosynthesis of steroid hormones have indicated that cholesterol can serve as a precursor of progesterone (12) and the adrenal cortical steroids (13). There is, however, some evidence that cholesterol is not a necessary intermediate in these biological syntheses (14). The conversion of cholesterol to estrogenic steroids has not been demonstrated. Heard et al. isolated C14-estrone from the urine of a pregnant mare to which CH8C14OONa was administered intravenously (15)) but found no Cl4 in the urinary estrone after cholesterol-4-Cl4 was given by the same route (16). Recently Heard et al. have reported the excretion of C14-labeled estrone by a pregnant mare to which C14-labeled testosterone was administered (17). This paper reports the results of an experiment in vitro carried out to study the possible biochemical conversion of testosterone to estrogenic steroids by human ovarian tissue.