Effect of pregnant mare's serum gonadotrophin on the activities of delta 4-5 alpha-reductase, aromatase, and other enzymes in the ovaries of immature rats.
After incubation of progesterone, 17 alpha-hydroxyprogesterone, androstenedione, and testostrone with an ovarian preparation (supernatant fluid at 10,000 x g) of immature rats (21-23 days of age) in the presence of NADPH, 3 alpha- and 3 beta-hydroxy-5 alpha-reduced steroids were obtained as the major metabolites. Among the enzyme activities relevant to the metabolism, delta 4-5 alpha-reductase and 3 beta-hydroxysteroid dehydrogenase were intracellularly localized to the microsomal fraction (10,000--105,000 x g), and 3 alpha-hydroxysteroid dehydrogenase was detected exclusively in the cytosol fraction (supernatant fluid at 105,000 x g). Within 2 days after a single injection of pregnant mare's serum gonadotrophin (10 IU/rat) to 21-day-old female rats, the following occurred: 1) an enhancement of 17 alpha-hydroxylase and C-17-C-20 lyase activities; 2) a suppression of delta 4-5 alpha-reductase activity; and 3) an increase in aromatizing activity. From the above-mentioned results, it was concluded that the increased secretion of estrogen from ovaries of immature rats stimulated by pregnant mare's serum gonadotrophin administration was caused by a modification of the ovarian enzyme activities relevant to estrogen production.
D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000378:metabolism*; D000735:Androstenedione / Q000378:metabolism; D000818:Animals; D001141:Aromatase / Q000378:metabolism*; D005260:Female; D006064:Gonadotropins, Equine / Q000494:pharmacology*; D006908:Hydroxyprogesterones / Q000378:metabolism; D006913:Hydroxysteroid Dehydrogenases / Q000378:metabolism; D007700:Kinetics; D006899:Mixed Function Oxygenases / Q000378:metabolism; D009929:Organ Size / Q000187:drug effects; D010053:Ovary / Q000201:enzymology*; D010088:Oxidoreductases / Q000378:metabolism*; D011284:Pregnenolone / Q000378:metabolism; D011374:Progesterone / Q000378:metabolism; D051381:Rats; D013739:Testosterone / Q000378:metabolism
D006064:Gonadotropins, Equine; D006908:Hydroxyprogesterones; D013739:Testosterone; D000735:Androstenedione; D011374:Progesterone; D011284:Pregnenolone; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; D006913:Hydroxysteroid Dehydrogenases; D001141:Aromatase; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase