Studies on steroid metabolism in human endometrial tissue

Abstract

1. A computerized technique is described for the quantitative determination of radiometabolites from incubation studies. 2. Seven steroid substrates have been incubated with human endometrial tissue. The principal radiometabolites were identified and determined after 2hr. incubation without the addition of cofactors and after 4hr. incubation with cofactors. 3. The main products from progesterone were 20α-dihydroprogesterone and 5α-pregnanedione with lower yields of 5β-pregnanedione and 20β-dihydroprogesterone. There was no evidence for 17α-hydroxylase activity. 4. 17α-Hydroxyprogesterone was transformed into small yields of 17α,20α- and 17α,20β-dihydroxypregn-4-en-3-one. In one incubation there was evidence for conversion into androstenedione. 5. Dehydroepiandrosterone was transformed into small amounts of androstenedione, 5α-androstanedione and androsterone. 6. Androstenedione and testosterone were interconvertible, the reaction favouring the formation of androstenedione. 5α-Androstanedione and androsterone were formed from both substrates. There was no evidence for the formation of phenolic steroids. 7. Oestrone and oestradiol-17β were interconvertible, the reaction favouring the formation of oestrone.