Figure. Concentration-dependent activation of NPY4R by NPY. Reporter cells were transfected with either the expression plasmid for neuro­pep­tide Y receptor Y4 (NPY4R) or the mock plasmid and treated with various concentrations of neuro­pep­tide Y (NPY). 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 29 nM.