Upregulation of estrogen receptor expression in the uterus of ovariectomized B6C3F1 mice and Ishikawa cells treated with bromoethane
- Laboratory of Experimental Pathology, National Institute of Environmental Health Sciences, P.O. Box 12233, MD C2-09, Research Triangle Park, NC 27709 (United States)
- Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 (United States)
- Biostatistics Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 (United States)
In a 2-year NTP bioassay, Bromoethane (BE) was found to induce endometrial neoplasms in the uterus of B6C3F1 mice [; ]. In women, hormonal influences, such as 'unopposed' estrogenic stimulus, have been implicated as important etiologic factors in uterine cancer. BE, however, does not affect the serum concentrations of sex hormones in female B6C3F1 mice [] and the mechanism of BE-induced uterine carcinogenesis still remains unclear. In the present study, we examined the estrogenic effects of BE on the uterus of ovariectomized B6C3F1 mice and on Ishikawa cells. Groups of 6 mice were given daily s.c. injections of 0, 100, 500 or 1000 mg BE/kg for 3 consecutive days. Mice treated with 17{beta}-estradiol served as positive controls. Mice were necropsied 24 h after the final injection, and uteri were weighed and examined histologically and immunohistochemically along with the vagina. Changes observed in the estrogen-treated mice included increased uterine weights, edema and inflammation of the endometrium, increased epithelial layers of the uterine and vaginal lumens and keratinization of the vaginal epithelium. In the BE-treated mice, no such changes occurred; however, immunohistochemical staining of the uterus revealed a significant increase in immunoexpression of the estrogen receptor alpha (ER{alpha}) in the two higher dose groups. Analysis of mRNA also showed slightly increased uterine ER{alpha} expression in these groups. Upregulated expression of ER{alpha} was confirmed in BE-treated Ishikawa cells, in which Western blotting analyses identified an intense signal at approximately 66 kDa, which is consistent with ER{alpha}. These data suggest that upregulated expression of ER{alpha} may be important in the induction of endometrial neoplasms in BE-treated mice.
- OSTI ID:
- 20783386
- Journal Information:
- Toxicology and Applied Pharmacology, Vol. 209, Issue 3; Other Information: DOI: 10.1016/j.taap.2005.04.012; PII: S0041-008X(05)00173-0; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0041-008X
- Country of Publication:
- United States
- Language:
- English
Similar Records
All-trans retinoic acid protects against arsenic-induced uterine toxicity in female Sprague-Dawley rats
Gene expression profiling in Ishikawa cells: A fingerprint for estrogen active compounds