[In vitro study of placental metabolism of (6,7-3H) estradiol -17 beta in guinea pigs].

The metabolism of (6-7-3H) estradiol-17 beta was studied in vitro in different cellular fractions of Guinea Pig placenta. The substrate was transformed into free as well as conjugated (hydrosoluble) estrone. It was thus possible to conclude, on one hand the existence of a very active microsomial 17 beta-hydroxy steroid-dehydrogenase and on the other the presence of a cytosolic system of estrogen conjugation. No estradiol-17 alpha or estriol were determined.