Histochemical Study of 3β- and 17β-Hydroxysteroid Dehydrogenases in Human Term Placenta

A histochemical study of the 3β- and 17β-hydroxysteroid dehydrogenases of human term placenta was carried out. The localization of the staining reaction using diformazan as the indicator varied with the steroids and pyridine nucleotides used. The staining reaction with 17β-estradiol and NAD was demonstrated in the trophoblast, stroma and vessels, whereas that with 17β-estradiol and NADP occurred only in the vessels. No formazan deposition was obtained with estriol. With testosterone, estr-4-en-17β-ol-3-one, 5αandrostan- 3α,17β-diol, and 5α-androstan-17β- ol-3-one and both pyridine nucleotides, a positive reaction was demonstrated only in the vessels. The straining reaction for 3β-hydroxysteroid dehydrogenase was localized in the trophoblast with all the 3β-hydroxysteroids tested. The greatest staining intensity was elicited with 5β-androstan-3β-ol-17-one and NAD or NADP. No formazan deposition was obtained with androsterone and 5β-androstan- 3α-ol-17-one with NAD and NADP. With androst-5-en-3β,17β-diol an...