Figure. Concentration-dependent activation of EDNRB by ET-1. Reporter cells were transfected with either the expression plasmid for endo­thelin receptor type B (EDNRB) or the mock plasmid and treated with various concentrations of endo­thelin 1 (ET-1). 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 5.0 nM.