3β-HYDROXYSTEROID DEHYDROGENASE ACTIVITY IN THE HUMAN FOETAL TESTIS

Abstract

Sections of testes from 9 human fetuses ranging in crown-rump length from 3.0 to 18.3 cm were incubated to determine 3V-hydroxysteroid dehydrogenase activity histochemically with the following steroids 3[beta]-hydroxy-pregn-5-en-20-one (pregnenolone); 3[beta], 17[alpha]-dihydroxy-pregn-5-en-20-one (17[alpha]-hydroxypregnenolone); 3[beta]-hydroxy-androst-5-en-17-one (DNA); 30, 17[beta]-dihydroxy-androst-5-ene (androstenediol); 3[beta]-sulphoxy-pregn-5-en-20-one (pregnenolone sulphate); 3[beta]-sulphoxy-17[alpha]-hydroxy-pregn-5-en-20-one (17[alpha]-hydroxy-pregnenolone sulphate); 3[beta]-sulphoxy-androst-5-en-17-one (DNAsulphate); 3[beta]-hydroxy-5[alpha]-androstan-17-one (epiandrosterone). Pregnenolone and DNA gave a color reaction in the interstitium of all testes studied. 17[alpha]-hydroxypregnenolone was utilised by testes from foetuses of C-R length 8.8 cm and over, androstenediol by testes from foetuses of C-R length 6.1 cm and over. These facts are thought to support the concept of separate substrate-specific 3B-hydroxysteroid dehydrogenases in the testis. Pregnenolone sulphate was used by the interstitial cells of all testes studied but gave a stronger reaction than the free steroid. 17[alpha]-hydroxypregnenolone sulphate was used by all foetal testes surveyed. DNA sulphate was not well used by the interstitial cells. The utilization of steroid sulphates in a different manner from the free steroids in this histochemical system may mean that the presence of a sulphate group affect enzyme-substrate binding or that a steroid sulphatase is involved. Intense formazan deposition followed incubation with epiandrosterone in all testes studied. This seems to imply that a [DELTA]5 configuration is not necessary for enzyme-substrate binding.