STEROID METABOLISM IN VITRO BY FOETAL SHEEP LIVER

Abstract

This paper reports the metabolism of labelled androstenedione and pregnenolone by the liver of foetal sheep. Isolation of reduction products was a major feature of this study. The livers were removed from sheep foetuses at (a) 129 days', and (b) 143 days' gestation immediately after Caesarean section under spinal analgesia. The tissue was maintained at 0 °C until incubated 1 h later. Chopped tissue (2 g) was incubated in 24 ml Krebs—Ringer bicarbonate glucose solution at 39–5 °C in 95% O2:5% CO2 with the following: incubation (a), 57·4 nmol each of [4-14C]androstenedione (34·8 mCi/mmol) and [7α-3H]pregnenolone (14·7 Ci/mmol); incubation (b), 57·4 nmol of [4-14C]androstenedione (34·8 mCi/mmol). Reactions were stopped after 2 h with acetone containing 500 μg each of the listed carrier steroids (Table 1). The following were unobtainable as sulphates and were added as free steroids to the conjugate fraction before