Mitochondrial pyruvate oxidation is increased in skeletal muscle from HFHS-fed ATX+/− mice. Mitochondrial respiration (A, D) and uncoupled respiration (B, E) during pyruvate oxidation (A, B) and fatty acid oxidation (D, E) in permeabilized soleus muscle fibers from chow- and HFHS-fed male WT and ATX+/− mice. C: Citrate synthase activity in fibers subjected to pyruvate oxidation analysis (n = 5–6). A–E: Statistical analysis was performed using a two-way ANOVA followed by a Tukey’s multiple comparison test. ##P < 0.01 versus chow; *P <0,05, **P < 0.01, ****P <0.0001 as indicated. M, malate; Pyr, pyruvate; Palm, palmitoyl-carnitine; D, ADP; Oct, octanoyl-carnitine; R, rotenone; S, succinate; AmA, antimycin A.