Effect of aging and ALDH2 on levels of AMPK, Sirt1 and mitochondrial proteins (UCP-2 and PGC-1α). A: AMPK; B: phosphorylated AMPK (pAMPK, Thr172); C: pAMPK-to-AMPK ratio; D: Sirt1; E: UCP-2; and F: PGC-1α. Insets: Representative gel blots for levels of AMPK, phosphorylated AMPK, Sirt1, UCP-2, PGC-1α and GAPDH (loading control) using specific antibodies; Mean ± SEM, n = 6 – 7 mice per group, * p < 0.05 vs. WT-young group, # p < 0.05 vs. WT-old group.