Metabolism of androstenedione by Sertoli cell enriched preparations and purified leydig cells from boar testes in relation to estrogen formation

Abstract

The metabolism of [ 3H]androstenedione in relation to estrogen formation was studied in incubations of Sertoli cell-enriched preparations (30–40% Sertoli cells) and purified Leydig cells (> 98%) from testes of mature male pigs. Radioactive metabolites were partitioned by countercurrent distribution (CCD) into unconjugated and ‘conjugated’ (water-soluble) fractions. Both unconjugated and solvolysed metabolites were separated into neutral and phenolic fractions by CCD with toluene and NaOH. The distribution of radioactivity was examined subsequently for each fraction by partition chromatography on celite columns. Major differences were noted in the products of metabolism from the two cell types. More than half of the radioactivity appeared in the conjugate fraction for Leydig cell incubations, but little or no conjugation occurred in Sertoli cell preparations. Metabolism of androstenedione to other neutral substances was extensive only for Leydig cells, with approx 2% remaining unchanged. No clear evidence of estrogen formation was observed with Sertoli cells; however, both unconjugated and conjugated phenolic fractions for Leydig cell products showed radioactivity corresponding to estrone and estradiol-17β on chromatography. About 2–5% of androstenedione was converted to these two estrogens, whereas most of the phenolic material was present as compounds more polar than estradiol.