Additive Estrogenic Activities of the Binary Mixtures of Four Estrogenic Chemicals in Recombinant Yeast Expressing Human Estrogen Receptor.

Kang KS, Cho SD,Lee YS.

Department of Veterinary Public Health, College of Veterinary Medicine, School of Agricultural Biotechnology, Seoul National University, Seodun-Dong, Kwonsun-Ku, Suwon 441-744, Korea.

To evaluate the estrogenic activities of several chemicals such as 17beta-estradiol (E2), rho-nonylphenol, bisphenol A, butylparaben, and combinations of these chemicals, we used recombinant yeasts containing the human estrogen receptor [Saccharomyces cerevisiae ER + LYS 8127]. We evaluated E2 was most active in the recombinant yeast assay, followed by rho-nonylphenol, bisphenol A, butylparaben. The combinations of some concentrations of 17-estradiol as a strong estrogen and bisphenol A or butylparaben as a weak estrogen showed additive estrogenic effects. Also, the combinations of some concentrations of nonlyphenol and butylparaben and combination of butylparaben and bisphenol A showed additive effects in the estrogenic activity. Therefore, the estrogenic activities of the combinations of two chemicals were additive, not synergistic.