Figure. Concentration-dependent activation of RXFP4 by relaxin-3. Reporter cells were transfected with the expression plasmid for relaxin family pep­tide/INSL5 receptor 4 (RXFP4) and treated with various concentrations of relaxin-3. 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.