17 beta-Hydroxysteroid oxidoreductase: a ubiquitous enzyme. Interconversion of estrone and estradiol-17 beta in BALB/c mouse tissues.
A survey was conducted to define the sites of 17 beta-hydroxysteroid oxidoreductase activity in organs and tissues of male and female BALB/c mice, as well as the favored direction of the oxidoreductase reaction in intact tissues. The enzyme activity was assayed by use of radiolabeled estrone and estradiol-17 beta as substrates. Estrone formation from estradiol-17 beta was demonstrated in all tissues. The formation of estradiol-17 beta from estrone was demonstrated in most tissues, however, it was barely detected or was undetectable in the glandular stomach, small intestine, cecum, and large intestine. Thus, 17 beta-hydroxysteroid oxidoreductase activity is expressed in all BALB/c mouse organs and tissues. Approximately two-thirds of the tissues and organs examined, including those of the reproductive tracts, favored the conversion of estrone to estradiol-17 beta rather than the reverse reaction. The results of this study, however, represent qualitative estimates of 17 beta-hydroxysteroid oxidoreductase activity in BALB/c mouse tissues that are uncorrected for conversion to hydroxylated metabolites. These in vitro findings suggest that the 17 beta-hydroxysteroid oxidoreductase catalyzed reduction of estrone may contribute to the maintenance of physiologic levels of estradiol-17 beta in estrogen responsive tissues.
D015067:17-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D000273:Adipose Tissue / Q000201:enzymology; D000818:Animals; D004064:Digestive System / Q000201:enzymology; D004702:Endocrine Glands / Q000201:enzymology; D004958:Estradiol / Q000096:biosynthesis / Q000378:metabolism*; D004960:Estradiol Dehydrogenases / Q000097:blood / Q000378:metabolism*; D004970:Estrone / Q000378:metabolism*; D005260:Female; D005836:Genitalia, Female / Q000201:enzymology; D005837:Genitalia, Male / Q000201:enzymology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009928:Organ Specificity; D012867:Skin / Q000201:enzymology; D014551:Urinary Tract / Q000201:enzymology
D004970:Estrone; D004958:Estradiol; D015067:17-Hydroxysteroid Dehydrogenases; D004960:Estradiol Dehydrogenases