Identification of steroids produced by bovine chorion incubated with [14C]androstenedione

Individual chorion taken from cows in early pregnancy (days 27, 44, 45 and 49) was incubated with [14C]androstenedione in short-term incubation in vitro. After preliminary extraction, separation and purification, metabolites were identified by recrystallization with authentic unlabelled steroids to constant specific activity. Major metabolites identified were 5 beta-androstane-3,17-dione (5 beta-androstanedione) and 5 beta-androstan-3 alpha-ol-17-one (aetiocholanolone) while minor metabolites were identified as 5 beta-androstane-3 alpha,17 beta-diol and 5 beta-androstan-17 alpha-ol-3-one. There was no 14C-labelled oestradiol or oestradiol detectable in the medium either as free oestrogens or as sulphates.