title: Estrogen 2-hydroxylase: activity in rat tissues.
abstract: Incubation parameters for a radioderivative assay for estrogen 2-hydroxylase have been examined. The assay was found to be specific and sensitive if a chromatographically purified preparation of COMT was used. Estradiol was found to be a better substrate for the 2-hydroxylase than estrone or estriol. The liver had significantly higher estrogen 2-hydroxylase activity than any other tissue examined. The estrogen 2-hydroxylase was highly localized in the microsomal fraction in both the liver and the brain. The male rat was found to have significantly more estrogen 2-hydroxylase activity in the liver than the female rat. In addition, in the male rat liver, the estrogen 2-hydroxylase activity was reversibly inducible by testosterone and was not affected by phenobarbital. In the male and female rat brain the estrogen 2-hydroxylase activities were similar.
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology; D002369:Castration; D002394:Catechol O-Methyltransferase / Q000378:metabolism; D019363:Cytochrome P-450 CYP1A1; D004967:Estrogens; D005260:Female; D007668:Kidney / Q000201:enzymology; D008297:Male; D008861:Microsomes / Q000187:drug effects / Q000201:enzymology*; D008862:Microsomes, Liver / Q000201:enzymology; D010053:Ovary / Q000201:enzymology; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats; D013250:Steroid Hydroxylases / Q000378:metabolism*; D013347:Subcellular Fractions / Q000201:enzymology; D013379:Substrate Specificity; D013737:Testis / Q000201:enzymology; D013739:Testosterone / Q000494:pharmacology
chemical_list: D004967:Estrogens; D013739:Testosterone; D013250:Steroid Hydroxylases; D019363:Cytochrome P-450 CYP1A1; C020120:estrogen 2-hydroxylase; D002394:Catechol O-Methyltransferase; D010634:Phenobarbital