|Hedges CP, Hickey AJ, McMahon CD, Smith HK (2012) A fiber-type-specific role for myostatin in regulating mitochondrial function. IBEC2012.|
Aim: This study aimed to compare mitochondrial oxygen consumption in C57BL/6J wild-type and myostatin-deficient mouse soleus and white gastrocnemius muscles.
Methods: Muscles were obtained from 4 month-old male mice. Mass-specific oxygen consumption (pmol.O2/mg/sec) was measured in permeabilised muscle, using high-resolution respirometry (Oroboros Oxygraph-2k). Maximal activities of citrate synthase and lactate dehydrogenase were determined by spectrophotometry.
Results: Myostatin-deficient soleus (n=6) consumed 20% more oxygen per mg than wild-type soleus (n=6) during oxidative phosphorylation. This was accompanied by greater citrate synthase and lactate dehydrogenase enzyme activity in myostatin-deficient soleus (29% and 80% respectively). Myostatin-deficient gastrocnemius (n=7) showed 26% lower oxygen consumption during uncoupled respiration, and 34% lower oxygen consumption when oxidising glycerol-3-phosphate compared to wild-type gastrocnemius (n=8). Citrate synthase activity was not significantly different and lactate dehydrogenase activity 26% greater in myostatin-deficient gastrocnemius compared to wild-type gastrocnemius.
Conclusion: These data suggest that myostatin-deficiency exerts fiber-type specific effects on skeletal muscle mitochondrial function.
Labels: MiParea: Respiration, Genetic knockout;overexpression, Comparative MiP;environmental MiP
Organism: Mouse Tissue;cell: Skeletal muscle Preparation: Permeabilized tissue Enzyme: TCA cycle and matrix dehydrogenases Regulation: Substrate Coupling state: OXPHOS
HRR: Oxygraph-2k, O2k-Spectrophotometer