Estrogen enhances induction of cytochrome P-4501A1 by 2,3,7, 8-tetrachlorodibenzo-p-dioxin in liver of female Long-Evans rats.
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- Published online on: January 1, 2000 https://doi.org/10.3892/ijo.16.1.141
- Pages: 141-148
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Abstract
A human carcinogen, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces liver tumors in female rats. In this study, we examined the effects of estrogen on an arylhydrocarbon receptor (AhR)-responsible protein, CYP1A1 expression induced by TCDD in female rat livers. The induction of CYP1A1 by a dose of 300 ng TCDD/kg and its resultant enzymatic activity were significantly enhanced by 5 microg 17beta-estradiol/kg body weight treatment to both intact and ovariectomized rats. Immunoblot analysis showed a increase in nuclear AhR due to estrogen, TCDD or both, suggesting that estrogen is involved in the activation of CYP1A1 gene after the formation of AhR-TCDD complex.
