Fig. 7.

Activation of recombinant rhinoceros ESR2 by phytoestrogens. HEK 293 cells were transiently cotransfected with SWR or GOHR ESR2 and estrogen response element-luciferase and β-gal reporter plasmids. Cells were then treated in triplicate with increasing concentrations (10⁻¹⁰ to 10⁻⁵ m) of coumestrol (A), genisein (B), daidzein (C), equol (D), or vehicle (0.01% EtOH or DMSO). Luciferase activity of treatments relative to vehicle-only treatment and normalized to β-gal activity was determined and used to calculate fold receptor activation. Data are presented as mean ± sem of the fold activation of each treatment divided by the fold activation of a 10⁻⁹ m E₂ treatment. Significant differences between mean SWR and GOHR ESR2 activation was determined using a Student's t test (*, P < 0.05; **, P < 0.01; n = 3–4).