INVITRO METABOLISM OF TESTOSTERONE BY CULTURED SERTOLI CELLS AND THE EFFECT OF FSH

Cultures of Sertoli cells isolated from testes of 18-and 36-day-old Long Evans rats were used to investigate their capacity to metabolize testosterone and the effect of FSH on such metabolism. Three different approaches were used: 1) investigation of the metabolism of radiolabeled testosterone under saturating substrate conditions; 2) study of the metabolism of radiolabeled testosterone utilizing trace amounts of high specific activity substrates; 3) the utilization of radioimmunoassay for measurement of estradio1-17β. The following steroids were isolated and identified by recrystallization to constant specific acitvity from the control and FSH-treated cultures: testosterone (unconverted substrate) androstenedione, dihydrotestosterone, 3α-hydroxy-5α-androstan-17-one and 5α-androstane 3α, 17β-diol. Radioimmunoassay data suggests that the Sertoli cells produce an estradiol-17β-like compound from unlabeled testosterone and that this production is stimulated by FSH. However, the radioactive metabolite from all our studies that behaved chromatographically like estradiol-17β failed to crystallize to constant specific activity, while in each experiment, authentic radiolabeled estradiol-17β added as recovery tracer did. The data demonstrate that: 1) cultures of Sertoli cells from immature rats have 5α-reductase, 3α- and 17β-hydroxysteroid oxidoreductase activities; 2) these enzymes may be affected by FSH; 3) based on radiolabeled metabolic techniques, Sertoli cells were unable to biotransform testosterone to estradio1-17β even in the presence of FSH. © 1979.