Fig. 7. The simulated pattern of D- and L-glucose radiolabeled probe absorption at the apical membrane in the presence of an initial high substrate concentration (100 mmol l^-1) varies according to whether absorption is primarily mediated or primarily passive. The same four different situations as shown in Fig. 6 are modeled, but the starting concentration of unlabeled D-glucose is 100 times higher. Notice that when passive absorption dominates (Aiv,Biv), the predicted cumulative absorption of D- and L-glucose probes as a function of time (Aiv) are much more similar than when mediated absorption dominates (Aiii). Analogously, when passive absorption dominates, the predicted absorption rates of D- and L-glucose probes as a function of time (Biv) are much closer than when mediated absorption dominates (Biii).