Fig. 7.

Skeletal muscle substrates, mitochondrial performance and content, and lipase phosphorylation with exercise. A and B: skeletal muscle glycogen (A) and triacylglycerol content (B) under sedentary (black bars) and submaximal endurance exercise (open bars) conditions {20 wk, fasted 3 h, biochemical analysis [red quadriceps], histology [gastrocnemius-plantaris-soleus complex (GPS)]; n = 4–6/group} normalized to control sedentary representative images (right) of histological analyses (GPS; n = 3/group). Interaction effect for triacylglycerol (P = 0.04). *P < 0.05 for exercise effect in SMAKO only. C: protein expression of phosphorylated hormone-sensitive lipase (p-HSL; Ser⁵⁶⁵, Ser⁶⁶⁰) normalized to total HSL and representative immunoblots (right) under sedentary (SED) and submaximal endurance exercise (E) conditions for control (C), SMAKO (S), and AAKO (A) (20 wk, fasted 3 h, tibialis anterior; n = 4–6/group). ^a,bP ≤ 0.05 for group difference; noncorresponding letters are different. ^c,dP < 0.05 for submaximal endurance exercise group difference, noncorresponding letters are different. *P < 0.05, effect of exercise. D: mitochondrial respiration in permeabilized muscle fibers (20 wk, fasted 12 h, soleus; n = 6/group). Oxygen consumption was measured following the sequential addition of the following substrates: palmitoylcarnitine, malate, ADP, glutamate, succinate, and FCCP. The corresponding respiratory states are noted: ADP-driven respiration (state 3), respiration in the absence of ADP (state 4), and uncoupled respiration (state U). ^GP < 0.05, effect of genotype, AAKO < control and SMAKO for each state. PM, palmitoylcarnitine + malate; PMD, palmitoylcarnitine + malate + ADP; PMGD, palmitoylcarnitine + malate + glutamate + ADP; PMGSD, palmitoylcarnitine + malate + ADP + glutamate + succinate. E: oxidative phosphorylation protein content of complexes I–V [NDUFB8 (complex I), SDHB (complex II), UQCRC2 (complex III), MTCO1 (complex IV), and ATP5A (complex V)] (20 wk, fasted 3 h, tibialis anterior; n = 6/group). Data are normalized to protein expression of β-actin. ^a,b,cP < 0.05, effect of genotype; noncorresponding letters are different. Representative immunoblots (right) for control (C), SMAKO (S), and AAKO (A).