LOCALIZATION OF TESTOSTERONE AND 3-BETA-HYDROXYSTEROID DEHYDROGENASE DELTA(5)-DELTA(4)-ISOMERASE IN CYNOMOLGUS MONKEY (MACACA-FASCICULARIS)TESTES

The enzyme 3 beta-hydroxysteroid dehydrogenase/Delta(5)-Delta(4)-isome rase (3 beta-HSD) is essential for the biosynthesis of all classes of steroid hormones, including androgens. We localized testosterone and 3 beta-HSD by light microscopic immunocytochemistry in the testes of ad ult cynomolgus monkeys. Immunoreactive testosterone was located as int ense deposits in the labeled cytoplasm of Leydig cells, and located we akly in the interstitial tissues, basement membranes, and the regions near tubular walls within tubules. Immunoreactive 3 beta-HSD was locat ed in the cytoplasm of all Sertoli cells and was especially intense in the parts near tubular walls and located weakly to intensely in the c ytoplasm of some Leydig cells. This is the first immunocytochemical ev idence that Sertoli cells of cynomolgus monkeys, as well as Leydig cel ls, are involved in biosynthesis of androgens.