Responses of BG1Luc cells at UCD to unstressed Tritan™ resin leachates. Concentration-response curves for BG1Luc cells (UCD) incubated with the indicated concentration of (A) E2 (M) or (B) specific extract equivalents (g/ml) of three Tritan™ thermoplastic resins for 24 hours and luciferase activity determined. (C) The three Tritan™ thermoplastic resins were each extracted in intra-assay triplicate with 100% EtOH repeated on three separate days (i.e., three repeated assays of the same type on the same unstessed resin). The maximum Luciferase activity was determined for each of the three repeated assays and expressed as the %RME2 ± SD for each resin. Solid black lines and data points show agonist activity for all data points not associated with toxicity (see Methods); red lines and data points show results of coincubation of BG1Luc cells with E2 or the leachates and 10-8 M ICI. Horizontal dotted line shows the 15%RME2 value that is significantly (p <0.01, Student’s T-test) greater than the VC and SC (i.e. at least 3 SD greater). This is a very conservative criterion for declaring a positive agonist response.