STEROIDOGENESIS IN TESTICULAR CELLS

The current state of knowledge concerning steroid biosynthesis and metabolism in isolated testicular cells is discussed. Data demonstrating conversion of progesterone to testosterone and 5α-reduced androgens in cultures of pure Sertoli cells derived from adult rat testes is presented. The constant ratio of total progesterone metabolism to total C-19 steroids observed in these studies suggests that the rate of androgen formation in Sertoli cells depends primarily upon the activities of the various steroidogenic enzymes. The data also suggest that the principal site of conversion of progesterone to androgens in the seminiferous tubules is the Sertoli cell and that the principal site of 5α-reductase activity in the testis is also the Sertoli cell. The Sertoli cell was also shown to be able to convert [14C]-testosterone to steroids with Chromatographic characteristics of oestrogens which were reactive in estradiol radioimmunoassay and their production was stimulated by FSH. However, they failed to crystallize to constant specific activity or constant ratio, while authentic [3H]-oestradiol 17-β used as tracer did crystallize. Thus, our studies failed to demonstrate conversion of testosterone to oestradiol-17β by cultured Sertoli cells. The identity of the steroids formed is currently under investigation. © 1979.