ABSTRACT
3β-Hydroxysteroid dehydrogenase activity was studied histochemically in the adrenal cortex of ten human male foetuses, ranging in crownrump length from 3.0 cm to 18.3 cm, with the following steroids:
3β-hydroxy-pregn-5-en-20-one (pregnenolone). 3β,17α-dihydroxy-pregn-5-en-20-one (17α-hydroxypregnenolone). 3β-hydroxy-androst-5-en-17-one (DHA). 3β,17β-dihydroxy-androst-5-ene (androstenediol). 3β-sulphoxy-pregn-5-en-20-one (pregnenolone sulphate). 3β-sulphoxy-17α-hydroxy-pregn-5-en-20-one (17α-hydroxy-pregnenolone sulphate) 3β-sulphoxy-androst-5-en-17-one (DHAsulphate). 3β-hydroxy-5α-androstan-17-one (epiandrosterone).
After incubation with pregnenolone, 17α-hydroxypregnenolone, DHA and androstenediol a positive histochemical reaction was obtained in the inner part of the »definitive« cortex and throughout the foetal cortex of all adrenals studied. Initially very weak, the reaction became strongly positive about the twelfth week of foetal life.
Pregnenolone sulphate and 17α-hydroxypregnenolong sulphate also gave a histochemical reaction in all the adrenals investigated, but DHA sulphate differed significantly from the free steroid by giving a very poor reaction.
Formazan deposition followed incubation with epiandrosterone in all adrenals used and this may imply that a δ5 configuration is not necessary for enzyme-substrate binding.