ASSESSING THE ESTROGENIC AND DIOXIN-LIKE ACTIVITIES OF CHEMICALS AND COMPLEX-MIXTURES USING IN-VITRO RECOMBINANT RECEPTOR-REPORTER GENE ASSAYS

In vitro recombinant receptor-reporter gene assays have been used to a ssess and rank the potency of chemicals and complex mixtures suspected of possessing estrogen and (or) aryl hydrocarbon receptor (AhR) media ted activity. The environmental estrogen (E(2)) bioassay consists of a Gal4-human estrogen receptor chimeric construct (Gal4-HEGO) and a Gal 4-regulated luciferase reporter gene (17m5-G-Luc) that have been stabl y integrated into HeLa cells. The assay exhibits 10-fold induction in luciferase reporter gene activity following treatment with 1 nM 17 bet a-estradiol and has a detection limit of approximately 5 pg of 17 beta -estradiol/mL. The AhR bioassay uses Hepa 1c1c7 wild-type cells transi ently transfected with a dioxin response element regulated luciferase reporter gene. These assays were used to assess the estrogen and dioxi n-like activities of naringenin, atrazine, and simazine and complex mi xtures such as pulp and paper mill. black liquor and urban air particu lates. The activities of these chemicals and complex mixtures are conf irmed using the pure antiestrogen ICI 164,384 and in in vitro gel reta rdation assays. Results of this study demonstrate the utility of in vi tro recombinant receptor-reporter gene assays in identifying and asses sing the estrogenic and dioxin-like activities of chemicals and comple x mixtures.