title: The effect of RMI 12, 936 synthetic antiprogestional steroid, on ovarian steroidogenesis in the rat.
abstract: A series of physiochemical investigations confirmed that the product of chemical and enzymatic isomerization of RMI 12,936 was 7alpha-methyltestosterone. The total activity per pair of ovaries of delta5 3-ketosteroid isomerase in vitro was unchanges by RMI 12,936 pretreatment or by advancing pregnancy, significant changes in ovarian weight being accompanied by reciprocal changes in enzyme activity/mg tissue. The initial rate of isomerization of RMI 12,936 was approximately five times greater than the corresponding rate of delta5-progesterone isomerization at equal substrate concentrations. It is concluded that RMI 12,936 does not inhibit progesterone biosynthesis by alteration of delta5 3-ketosteroid isomerase activity, but that it may do so by acting as an alternative substrate for this enzyme.
mesh_terms: D000737:Androstenols / Q000494:pharmacology*; D000818:Animals; D003276:Contraceptives, Oral / Q000494:pharmacology*; D003280:Contraceptives, Oral, Synthetic / Q000494:pharmacology*; D005260:Female; D005865:Gestational Age; D008777:Methyltestosterone / Q000378:metabolism; D009929:Organ Size; D010053:Ovary / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D011247:Pregnancy; D011374:Progesterone / Q000037:antagonists & inhibitors*; D051381:Rats; D013251:Steroid Isomerases / Q000378:metabolism
chemical_list: D000737:Androstenols; D003276:Contraceptives, Oral; D003280:Contraceptives, Oral, Synthetic; D011374:Progesterone; C010528:17-beta-hydroxy-7 alpha-methyl-androst-5-en-3-one; D013251:Steroid Isomerases; D008777:Methyltestosterone