HISTOCHEMICAL DISTRIBUTION OF SOME HYDROXYSTEROID DEHYDROGENASES IN THE PLACENTA, FOETAL MEMBRANES AND UTERINE MUCOSA OF THE MOUSE

Abstract

SUMMARY The placenta, foetal membranes and uterine mucosa of mice (pregnant for 8–17 days) have been investigated by histochemical methods for NAD-dependent 3β-hydroxysteroid dehydrogenase (3β-HSDH), and for NAD-and NADP-dependent 17α- and 17β-hydroxysteroid dehydrogenases (17α- and 17β-HSDH), 11α- and 11β-hydroxysteroid dehydrogenases (11α- and 11β-HSDH), and 20β-hydroxysteroid dehydrogenase (20β-HSDH). 3β-HSDH was found to be distributed in the trophoblastic giant cells of the first generation with both pregnenolone and DHA as substrates, and in the giant cells of the second generation and of the labyrinth and the endodermal cells of the inverted yolk sac placenta, but only with DHA as substrate. 17α-HSDH and 17β-HSDH, NAD-dependent, were present in both the first and second generation giant cells and in the giant cells of the labyrinth as well as in the endodermal cells of the inverted yolk sac placenta. With NADP as cofactor, 17α-HSDH and 17β-HSDH were weakly positive with all the substrates used in the giant cells of the second generation and of the labyrinth, while NADP-dependent 17β-HSDH was present in the first generation giant cells and in the endodermal cells of the inverted yolk sac placenta but only with oestradiol-17β as substrate. The histochemical reaction for 11α-HSDH, both NAD- and NADP-dependent, was limited to trophoblastic giant cells of the second generation and of the labyrinth; 11β-HSDH, both NAD- and NADP- dependent, was distributed in the giant cells of the second generation and of the labyrinth, the epithelial cells of the uterine mucosa and the decidua basalis. The histochemical reaction for 20β-HSDH, NAD- and NADP-dependent, was weakly positive in the giant cells of the first generation only.