MIBE is a ligand of GPER and ERalpha. (a) MIBE competes with [3H]E2 for the binding to ERalpha. Competitive binding of increasing concentrations of unlabelled E2, OHT and MIBE to recombinant human ERalpha protein. Each data point represents the mean ± SD of triplicate samples of three separate experiments. (b) Ligand binding assay in SkBr3 cells. Competition curves of increasing concentration of unlabelled E2, G-1, OHT and MIBE expressed as a percentage of maximum specific [3H]E2 binding. Each data point represents the mean ± SD of three separate experiments performed in triplicate.