Figure. Concentration-dependent activation of GHSR by ghrelin. Reporter cells were transfected with either the expression plasmid for growth hormone secre­ta­gogue receptor (GHSR) or the mock plasmid and treated with various concentrations of ghrelin. 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 4.0 nM.