title: Steroid metabolism in pregnant hamster. I. Metabolism of [4-14C] pregnenolone and [4-14C] progesterone by hamster placental tissue in vitro.
abstract: Quartered placentae from 12- and 15-day pregnant hamsters were incubated with 14C labelled pregnenolone and progesterone and products of their conversion, were identified by chromatographic and isotope dilution methods. Pregnenolone was converted to progesterone, 7 alpha-hydroxypregnenolone, 7 alpha-hydroxyprogesterone, 3 alpha--hydroxy-5 beta-pregnan-20-one, 3 beta-hydroxy-5 alpha-pregnan-20-one, 3 alpha-hydroxy-5 alpha-pregnan-20-one, 5 beta-pregnane-3,20-dione and 5 alpha-pregnane-3,20-dione. Except for 7 alpha-hydroxypregnenolone, the same metabolites were identified in incubates of the placental tissue with progesterone. Thus, the activity of delta 5-3 beta-hydroxysteroid dehydrogenase and delta 5 leads to 4 isomerase, 7 alpha-hydroxylase, 3 beta- and 3 alpha-hydroxysteroid dehydrogenase, delta 4-5 beta- and delta 4-5 alpha-reductase enzyme systems was shown in hamster placenta. The formation of androgens from pregnenolone, progesterone and their 17-hydroxy-derivatives was not observed. There was also no evidence for the formation of estrogens from the above C-21 steroid precursors.
mesh_terms: D006907:17-alpha-Hydroxypregnenolone / Q000378:metabolism; D000818:Animals; D006224:Cricetinae / Q000378:metabolism*; D005260:Female; D006908:Hydroxyprogesterones / Q000378:metabolism; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011270:Pregnancy, Animal; D011284:Pregnenolone / Q000378:metabolism*; D011374:Progesterone / Q000378:metabolism*
chemical_list: D006908:Hydroxyprogesterones; D006907:17-alpha-Hydroxypregnenolone; D011374:Progesterone; D011284:Pregnenolone