Pre-ovulatory changes in steroidogenesis in ovaries from immature rats treated with pregnant mare serum gonadotrophin.
The metabolism of progesterone in the 1000 g supernatant fraction of homogenates of ovaries from PMSG-treated immature rats was determined. As early as 52 h after a single injection of 50 i.u. PMSG, still before the LH surge, 5alpha-pregnane-3alpha, 20alpha-diol was identified as the main metabolite, together with small quantities of 3alpha-hydroxy-kalpha-pregnan-20-one and 5alpha-androstane-3alpha, 17beta-diol. Similar incubations of untreated rat ovaries at the same age did not produce 5alpha-pregnane-3alpha, 20alpha-diol. The quantities of 3alpha-hydroxy-5alpha-pregnan-20-one and 5alpha-androstane-3alpha, 1mbeta-diol were reduced in PMSG-treated rat ovaries as compared with control ovaries. When progesterone metabolism was examined 64 h after PMSG administration, 5-7 h after the peak of LH surge but still before ovulation, 75% of the substrate was converted to 5alpha-pregnane-3alpha, 20alpha-diol, while 3alpha-hydroxy-5alpha-pregnan-20-one as well as 5alpha-androstane-3alpha, 17beta-diol could not be detected.
D000367:Age Factors; D015114:Androstenediol / Q000032:analysis; D000818:Animals; D002849:Chromatography, Gas; D005260:Female; D006064:Gonadotropins, Equine / Q000494:pharmacology*; D066298:In Vitro Techniques; D010053:Ovary / Q000187:drug effects* / Q000378:metabolism; D011276:Pregnanediol / Q000032:analysis; D011278:Pregnanes / Q000032:analysis; D011280:Pregnanolone / Q000032:analysis; D011374:Progesterone / Q000096:biosynthesis; D051381:Rats
D006064:Gonadotropins, Equine; D011278:Pregnanes; D011374:Progesterone; D015114:Androstenediol; D011280:Pregnanolone; D011276:Pregnanediol