Formation of 3H2O from [2-3H]- and [4-3H] estradiol by rat uteri in vitro: possible role of peroxidase.
The mitochondrial fraction of diethylstilbestrol-treated rat uteri, known to contain an estrogen-induced peroxidase, was able to catalyze the release of 3H2O from either [2-3H]- or [4-3H]estradiol. Hydrogen peroxide added to this system increased the yield of 3H2O but had no effect on mitochondrial preparations from ovariectomized rat uteri having only very low peroxidase activity. The reaction was inhibited by catalase and also occurred with lactoperoxidase in the presence of H2O2 but 2-hydroxyestradiol was not detected in any of these experiments. Under similar conditions, tyrosinase catalyzed the formation of the catechol estrogen with loss of 3H from [2-3H]- or [2,4,6,7-3H]- but not [4-3H]- or [6,7-3H]estradiol. It is proposed that the formation of 3H2O from 3H-labeled estradiol in the estrogen-treated rat uterus may occur by a peroxidative mechanism which does not necessarily result in hydroxylation of the steroid.
D000818:Animals; D002250:Carbon Radioisotopes; D004054:Diethylstilbestrol / Q000494:pharmacology; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology*; D010544:Peroxidases / Q000378:metabolism*; D051381:Rats; D014316:Tritium; D014599:Uterus / Q000187:drug effects / Q000378:metabolism*; D014867:Water
D002250:Carbon Radioisotopes; D014867:Water; D014316:Tritium; D004958:Estradiol; D004054:Diethylstilbestrol; D010544:Peroxidases