Figure 3: Dependency of H+-efflux on extracellular H+ concentration. (A) Original recordings of the intracellular H+ concentration in MCT1-expressing oocytes injected either with 50 ng of CAII (black trace) or H2O (gray trace), respectively, during application of 10 mM lactate in HEPES buffered solution at pHo 6.5 followed by removal of lactate at extracellular pH of 5.0, 6.0, 7.0, and 8.0, respectively. (B) Rate of change in intracellular H+ concentration in MCT1-expressing oocytes injected either with CAII (50 or 200 ng) or H2O as induced by removal of 10 mM lactate at varying extracellular pH. (C) Simulation of the rate of change in intracellular H+ concentration in MCT1-expressing oocytes with varying concentrations of CAII as induced by removal of 10 mM lactate at varying extracellular pH.