Figure. Concentration-dependent activation of GPBAR1 by TGR5 agonist. Reporter cells were transfected with the expression plasmid for G protein-coupled bile acid receptor 1 (GPBAR1) and treated with various concentrations of TGR5 agonist. Data points shown are the mean ± SEM of an experiment performed in triplicate, and the curve is a fit to Hill equation with an EC50 of 350 nM.