Figure. Concentration-dependent activation of GIPR by GIP. Reporter cells were transfected with the expression plasmid for gas­tric in­hib­i­to­ry poly­pep­tide receptor (GIPR) and treated with various concentrations of gas­tric in­hib­i­to­ry poly­pep­tide (GIP). 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 3.4 nM.