title: [Comparative study of the 3 beta-hydroxy-delta 5-steroid dehydrogenase activity of the mitochondrial and microsomal fractions of human and cat placentas].
abstract: Delta 5, 3 beta hydroxysteroid dehydrogenase activity was studied on mitochondrial and microsomal fractions of human and cat placentas. This activity was assessed by measuring the rate of [3H] progesterone formation from [3H] pregnenolone and of [3H] delta 4-androstenedione from [3H] dehydroepiandrosterone (DHA), by a double isotope dilution method. Specific activities measured under initial velocity conditions were similar in both human and cat placentas. However, the kinetics of the reaction with DHA as substrate exhibit a zoological specificity.
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D000818:Animals; D002415:Cats; D003687:Dehydroepiandrosterone; D005260:Female; D006801:Humans; D007700:Kinetics; D008861:Microsomes / Q000201:enzymology*; D008928:Mitochondria / Q000201:enzymology*; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D011375:Progesterone Reductase / Q000378:metabolism*; D013045:Species Specificity; D013379:Substrate Specificity
chemical_list: D003687:Dehydroepiandrosterone; D015096:3-Hydroxysteroid Dehydrogenases; D011375:Progesterone Reductase
vernacular_title: Etude comparée de l'activité delta 5, 3 beta hydroxystéroïde deshydrogénase des fractions mitochondriales et microsomales de placentas humains et de chatte.