Dose-dependent aggregometry data for ADP-induced platelet shape change at different Iloprost concentrations. The half-maximal ADP concentration for platelet shape change increased from 48 nM to 217 nM in the presence of 1 nM Iloprost, whereas the Hill-slope of the dose-response curve increased from 1.05 to 1.92 (means of 4 independent experiments ± standard deviation). Hill coefficients were calculated by nonlinear regression analysis of the raw data.