Cardiac mitochondrial phenotype of cardiac-specific knockout mice after 11 months of Sirt1 deletion. (A) Rate of respiration after successive addition of l-glycerol-3-phosphate (4 mM) (g3p), palmitoyl-CoA and carnitine (100 µM and 2 mM) (p-CoA), pyruvate (1 mM) (pyr), glutamate (10 mM) (glu), succinate (15 mM) (succ), amytal (1 mM), and N, N′, N′-tetramethyl-phenylenediamine dihydrochloride (TMPD)-ascorbate (0.5 mM). (B) Citrate synthase (CS) and cytochrome c oxidase (COX) enzymatic activities. (C) Immunoblotting of citrate synthase (CS) and voltage-dependent anion channel (VDAC) in LV homogenates. (D) Total protein content of 5 subunits of oxidative phosphorylation complexes: C-I-20 (complex I (CI)), C-II-30 (complex II (CII)), C-III-Core 2 (complex III (CIII)), C-IV-COXI (complex IV (CIV)), and C-V-α (complex V (CV)). Protein content for CI, CII, CII, and CIV was normalized using CV as internal control. (E) Net rate of H2O2 release by the mitochondrial electron transport chain measured following sequential addition of succinate (5 mM), and ADP (1 mM). (F) SOD2 protein content in LV homogenates. (A–B and E: n = 6 to 7 per experimental group, C–D and F: n = 4 per experimental group), * p < 0.05 Sirt1f/f versus Sirt1ciKO.