Multi-experimental data fit. Means of three independent cAMP measurements (circles) and estimated standard error of the mean, resulting of cAMP elevating platelet treatments as PDE3 inhibition (A, B) and activation of adenylyl cyclase (C, D) through administration of varying drug doses. Displayed curves reflect predicted model trajectories of the optimized pathway models: Models for PDE inhibition and AC activation were fit simultaneously to all displayed data (of number data points N =155; χ2 = 129.08), by precisely estimating a set of only 23 parameters in total. Top: Inhibition of PDE3 with different concentrations of Cilostamide (A) and Milrinone (B) Bottom: Model trajectories and measurements after adenylyl cyclase stimulation with different concentrations of Iloprost (C) and Forskolin (D). Colors: Varying concentrations of given drug stimuli (hardly any cAMP elevating effect of Cilostamide at low administered doses).