Hitomi Takemura

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In the present study, we compared the estrogenic activity of zearalenone (ZEN) and zeranol (ZOL) by determining their relative receptor binding affinities for human ERalpha and ERbeta and also by determining their uterotropic activity in ovariectomized female mice. ZOL displayed a much higher binding affinity for human ERalpha and ERbeta than ZEN did. The(More)
CYP1A1 and CYP1A2 exhibit catalytic activity predominantly for the 2-hydroxylation of estradiol, whereas CYP1B1 exhibits catalytic activity predominantly for 4-hydroxylation of estradiol. To understand why CYP1B1 predominantly hydroxylates the 4-position of estradiol, we constructed three-dimensional structures of CYP1A1 and CYP1B1 by homology modeling,(More)
A 17beta-estradiol (E(2)) is hydrolyzed to 2-hydroxy-E(2) (2-OHE(2)) and 4-hydroxy-E(2) (4-OHE(2)) via cytochrome P450 (CYP) 1A1 and 1B1, respectively. In estrogen target tissues including the mammary gland, ovaries, and uterus, CYP1B1 is highly expressed, and 4-OHE(2) is predominantly formed in cancerous tissues. In this study, we investigated the(More)
Risk factors for breast cancer include estrogens such as 17β-estradiol (E2) and high stress levels. 4-Hydroxyestradiol (4-OHE2), a metabolite of E2 formed preferentially by cytochrome P450 1B1, is oxidized to E2-3,4-quinone, which reacts with DNA to form depurinating adducts that exert genotoxicity and carcinogenicity. Endogenous catecholamines such as(More)
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