Comparing predicted dynamics of the normalized-Hill model with a detailed biochemical model. The left panel shows normalized dynamic responses of Gsα and PLB phosphorylation predicted by the biochemical model during a transient 10 nM NE exposure. Normalized-Hill model predictions of the same outputs during a similar NE exposure are shown in the right panel. Activity levels and dynamics of the normalized-Hill model traces were fit to those of the biochemical model via least-squares parameter estimation. In all, 11 parameters were adjusted (4 τ's, 3 W's, 3 EC50's, and an additional basal receptor activity term) to mimic biochemical model outputs using the normalized-Hill model.