Effects of CCCP on concentrations of R123 and TMRE in medium surrounding cell-coated beads. A: [Re] for R123 in samples containing R123 only (control, n = 11) or R123 + CCCP (n = 4). B: at 150 min (dotted vertical line), CCCP was added to 4 R123 samples and to all R123 + CCCP samples. C: [Re] for TMRE (control, n = 4) or TMRE + CCCP (n = 4). D: at 60 min (dotted vertical line), CCCP was added to all 4 TMRE samples and all 4 TMRE + CCCP samples. Symbols are data (means ± SE). Solid lines, model fit to data; dashed lines, model predictions using Table 1 parameter values.