title: Human placental delta 5-3 beta-hydroxysteroid dehydrogenase, delta 4,5 isomerase: in vitro effect of dehydroepiandrosterone and allyestrenol.
abstract: The in vitro effects of dehydroepiandrosterone (DHA) and allylestrenol on human placental delta 5- 3 beta-hydroxysteroid dehydrogenase, delta 4,5 isomerase activity (delta 5-3 beta-HSDH) was investigated by incubation of subcellular fractions with [4-14C] pregnenolone. It has been found that DHA inhibits the delta 5-3 beta-HSDH activity up to -81% at 5 X 10-5 M concentration while allylestrenol seems to be able to lightly stimulate the delt a 5-3 beta-HSDH activity with a maximum effect (+15-26%) at 5 X 10-7 M concentration. The data concerning allylestrenol, seem of particular interest as this compound is used as a progestative drug during pregnancy, if one consider the inhibitory effect exerted by several natural and synthetic steroids on the delta 5-3 beta-HSDH activity.
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D000500:Allylestrenol / Q000494:pharmacology*; D003687:Dehydroepiandrosterone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004963:Estrenes / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007700:Kinetics; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D011375:Progesterone Reductase / Q000378:metabolism*; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D004963:Estrenes; D003687:Dehydroepiandrosterone; D015096:3-Hydroxysteroid Dehydrogenases; D011375:Progesterone Reductase; D000500:Allylestrenol