Luciferase reporter gene assay for transcription inhibitory activity for ERβ

In the in vitro luciferase reporter gene assay to measure qualitatively the antagonistic activity of bisphenols for ERβ, a serial concentration of bisphenols (10⁻¹³ to 10⁻⁵ M in the final solution) was assayed in the HeLa cells in the presence of 10 nM E2, which elicits a full activation of ERβ. Each assay was performed exactly as described above for transcription activation activity. In order to measure quantitatively the antagonistic activity of bisphenols for ERβ, four different concentrations (0.01, 0.1, 1.0, and 10 μM) of the respective bisphenol were examined for a serial concentration of 17β-estradiol (10⁻¹³ to 10⁻⁵ M in the final solution).