Activity of Human Placental Sulfatase and 11β-Hydroxysteroid Dehydrogenase with Respect to Steroids of the Pregn-4-ene C-21-yl Sulfate Series

Abstract

Sulfatase and 11β-hydroxysteroid dehydrogenase activities of human placenta were studied with respect to four steroids of the pregn-4-ene C-21-yl-sulfate series. Homogenates, as well as the microsomal fraction of placenta obtained either at midterm or at term, possessed negligible sulfatase activity with respect to the sulfates of 11-dehydrocorticosterone and corticosterone, and low but consistent activity towards 11-deoxycorticosterone sulfate. Under the same conditions dehydroepiandrosterone sulfate was hydrolyzed almost quantitatively.Placental homogenates converted cortisol to cortisone and corticosterone to 11-dehydrocorticosterone. The reaction was greatly enhanced by the addition of NADP. In contrast, the corresponding 11β-hydroxy-C-21 steroid sulfates were poor substrates with respect to placental 11β-hydroxysteroid dehydrogenase, as indicated by the low yields of the sulfates of cortisone and 11-dehydrocorticosterone, even in the presence of NADP. These findings are consistent with the pattern of steroids of the pregn-4-ene series characterized in human cord plasma.

Untersuchungen zur Regulation von hCG durch Kortisol (Prednisolon) in der Trophoblastzelle in vitro

“…Die Oxidation von Kortisol zu Kortison ist bis zu siebenmal gröûer als die Reduktion von Kortison zu Kortisol [17]. Ein Schlüsselenzym ist die 11b-HSD in der menschlichen Plazenta [7]. Es existieren zwei Typen der 11b-HSD.…”