| Rapid Screening of Environmental Chemicals for Estrogen Receptor Randall Bolger,1 Thomas E. Wiese,2 Kerry Ervin,1 Scott Nestich,1 and William Checovich1 1PanVera Corporation, Madison, WI 53711 USA
2Curriculum in Toxicology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA Abstract
Over the last few years, an increased awareness of endocrine disrupting chemicals (EDCs) and their potential to affect wildlife and humans has produced a demand for practical screening methods to identify endocrine activity in a wide range of environmental and industrial chemicals. While it is clear that in vivo methods will be required to identify adverse effects produced by these chemicals, in vitro assays can define particular mechanisms of action and have the potential to be employed as rapid and low-cost screens for use in large scale EDC screening programs. Traditional estrogen receptor (ER) binding assays are useful for characterizing a chemical's potential to be an estrogen-acting EDC, but they involve displacement of a radioactive ligand from crude receptor preparations at low temperatures. The usefulness of these assays for realistically determining the ER binding interactions of weakly estrogenic environmental and industrial compounds that have low aqueous solubility is unclear. In this report, we present a novel fluorescence polarization (FP) method that measures the capacity of a competitor chemical to displace a high affinity fluorescent ligand from purified, recombinant human ER- at room temperature. The ER- binding interactions generated for 15 natural and synthetic compounds were found to be similar to those determined with traditional receptor binding assays. We also discuss the potential to employ this FP technology to binding studies involving ER-ß and other receptors. Thus, the assay introduced in this study is a nonradioactive receptor binding method that shows promise as a high throughput screening method for large-scale testing of environmental and industrial chemicals for ER binding interactions. Key words: competition binding, endocrine disruptor screening, estrogen, estrogen receptor, fluorescence polarization. Environ Health Perspect 106:551-557 (1998) . [Online 6 August 1998] http://ehpnet1.niehs.nih.gov/docs/1998/106p551-557bolger/ abstract.html Address correspondence to R. Bolger, PanVera Corporation, 545 Science Drive, Madison, WI 53711 USA. We thank William R. Kelce, L. Earl Gray, and Susan C. Laws of the Reproductive Toxicology Division, National Health and Environmental Effects Research Laboratory, for providing many of the test chemicals used in this study. Support for T.E.W. was provided by the EPA/UNC Toxicology Research Program, training agreement T901915. This manuscript has been reviewed in accordance with the policy of the National Health and Environmental Effects Research Laboratory, U.S. EPA, and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. Received 3 February 1998 ; accepted 14 April 1998.
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