3β-HYDROXYSTEROID DEHYDROGENASE ACTIVITY IN THE MOUSE LEYDIG CELL

Abstract

SUMMARY One hundred and thirty-two male Swiss white mice were killed in batches of twelve, between birth and the end of the 10th week of postnatal life inclusive, a total of eleven groups. Sections of testis from every animal were incubated with three steroid substrates to demonstrate 3β-hydroxysteroid dehydrogenase histochemically. The substrates were (1) 3β: 17α-dihydroxypregn-5-en-20-one (17α-hydroxypregnenolone), (2) 3β-hydroxypregn-5-en-20-one (pregnenolone) and (3) 3β-hydroxyandrost-5-en-17-one (DHA). When 17α-hydroxypregnenolone was used as a substrate no 3β-hydroxysteroid dehydrogenase activity was demonstrable in the testis until the end of the 10th week of postnatal life. With pregnenolone as a substrate 3β-hydroxysteroid dehydrogenase activity was demonstrable throughout the age groups studied. It was present at birth and increased progressively until the end of the 6th week of postnatal life. Thereafter the activity decreased progressively during the ensuing 4 weeks. With DHA as substrate activity was again demonstrable in all age groups studied and increased progressively from birth until the end of the 7th week of postnatal life after which a relatively constant high level was maintained. On the basis of these findings the existence of more than one 3β-hydroxysteroid dehydrogenase enzyme is postulated, each enzyme being substrate specific.