title: Effect of estradiol-17 beta on the conversion of pregnenolone to progesterone in human term placenta incubated in vitro.
abstract: The effect of different doses of estradiol-17 beta (E2) on the metabolic pregnenolone to progesterone pathway in fragments of human term placenta incubated in vitro was studied. Doses considered as being physiological of 0.09 and 0.9 microM had a stimulatory effect on the conversion (p less than 0.008 to 0.016). However, a supraphysiological dose of 45 microM showed an inhibitory activity related to the maximal stimulation (p less than 0.03). A dose of 0.9 microM E2 favoured the accumulation of (3H)-progesterone in the tissue (p less than 0.05). These results suggest that E2 may regulate the synthesis of progesterone in human term placenta.
mesh_terms: D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D010920:Placenta / Q000187:drug effects / Q000378:metabolism*; D011247:Pregnancy; D011284:Pregnenolone / Q000378:metabolism*; D011374:Progesterone / Q000096:biosynthesis*; D014316:Tritium
chemical_list: D014316:Tritium; D011374:Progesterone; D004958:Estradiol; D011284:Pregnenolone