title: Biosynthesis of 3 beta-hydroxy-5,7-pregnadien-20-one by the horse fetal gonad.
abstract: The production of equilin and the other ring B-unsaturated estrogens by the pregnant mare is anomalous in that they are biosynthesised by a cholesterol-independent pathway. Fetal horse gonads were incubated with tritiated sodium acetate and radiochemically pure 3 beta-hydroxy-5,7-pregnadien-20-one and 3 beta-hydroxy-5,7-androstadien-17-one were isolated. A fetal gonad--placental system is proposed for equilin production, 3 beta-hydroxy-5,7-pregnadien-20-one being a precursor for 3 beta-hydroxy-5,7-androstadien-17-one in the fetal gonad and the latter being the precursor of equilin in the placenta. The nature of the possible precursor of 3 beta-hydroxy-5,7-pregnadien-20-one is discussed.
mesh_terms: D000818:Animals; D003687:Dehydroepiandrosterone / Q000378:metabolism; D004857:Equilin / Q000096:biosynthesis; D006066:Gonads / Q000196:embryology / Q000378:metabolism*; D006736:Horses / Q000196:embryology*; D066298:In Vitro Techniques; D011245:Pregnadienes / Q000096:biosynthesis*; D011284:Pregnenolone / Q000378:metabolism
chemical_list: D011245:Pregnadienes; D004857:Equilin; D003687:Dehydroepiandrosterone; D011284:Pregnenolone; C037376:3-hydroxy-5,7-pregnadien-20-one