The role of AMPK activation in protecting mitochondrial function. A) Inhibition of RGE-induced AMPKα phosphorylation by compound C treatment. Cells were incubated with RGE for 30 min following treatment of 5 μM compound C for 30 min. Results were confirmed by repeated experiments. B) Reversal of the effect of RGE on MMP by compound C. After treatment with 5 μM compound C for 30 min, cells were incubated with RGE and/or iron + AA. The subpopulation of M1 fraction was analyzed as described in the legend to Figure 3A. Data represent the mean ± S.E.M. of three replicates (treatment mean significantly different from iron + AA, **p < 0.01). NS, not significant. C) A schematic diagram illustrating the proposed mechanism by which RGE protects hepatocytes against AA + iron-induced oxidative stress.