title: Activation by corticosteroids of steriod metabolizing enzymes in ovine placental explans in vitro.
abstract: A technique has been developed for the study of placetal steroid synethesis in tissue culture. Explants of sheep placentas recovered in the last third of gestation produced progesterone and converted labelled androstenedione into unconjugated and conjugated oestrogens. Cortisol added to the medium stimulated 17 alpha-hydroxylase and aromatizing enzyme activities. The results are discussed in relation to the proposal that the rise in secretion of fetal cortisol before parturition has a direct effect on the activation of placental enzymes catalysing the conversion of progesterone to eostrogens.
mesh_terms: D000735:Androstenedione / Q000378:metabolism; D000818:Animals; D046508:Culture Techniques; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D006854:Hydrocortisone / Q000378:metabolism / Q000494:pharmacology*; D010920:Placenta / Q000033:anatomy & histology / Q000201:enzymology*; D011247:Pregnancy; D011374:Progesterone / Q000096:biosynthesis; D012756:Sheep; D013254:Steroid 17-alpha-Hydroxylase / Q000378:metabolism
chemical_list: D000735:Androstenedione; D011374:Progesterone; D013254:Steroid 17-alpha-Hydroxylase; D006854:Hydrocortisone