Aromatase activity in monolayer cell cultures of human endometrium

Monolayer cell cultures of proliferative human endometrial stromal cells were incubated with 100 nCi 3H-androstenedione or 100 nCi 3H-testosterone for 15 hours. After termination of the incubations 16% of the recovered radioactivity was identified as estrone by thin layer chromatography and subsequent recrystallization. 3H-testosterone was almost quantitatively converted to 3H-androstenedione. 3H-dihydrotestosterone remained unmetabolized. These findings indicate a highly active 17 beta-ol-dehydrogenase and a high aromatizing capacity of human endometrial cells.