Metabolism of progesterone-4-¹⁴C in porcine uterine endometrium

Endometrial tissue from gilts, which were sacrificed on day 9 or 10 of the estrous cycle, was incubated in vitro with progesterone- 4-¹⁴C. Approximately 60% of the labeled substrate was converted to metabolic products. Ten products were isolated and 2 were identified by chromatographic techniques, derivative formation and recrystallization to constant specific activity. These 2 compounds were 5-pregnane- 3, 20-dione and 3β-hydroxy-5a-pregnan-20-one. Chromatographic evidence was obtained for the formation of 20αhydroxypregn-4-en-3-one and 20αhydroxy-5β-pregnan-3-one. It was noted during the extraction of the metabolites from water with dichloroethane that 36% of the radioactivity remained in the aqueous phase. Repeated extractions removed an additional 0.3% of the radioactivity.