MSTN and Insulin resistance: Despite insulin resistance and muscle atrophy, M-p110αKO mice show decreased serum myostatin, increased mitochondrial mass, increased mitochondrial fusion, and increased PGC1α expression, especially PCG1α2 and PCG1α3. This leads to enhanced mitochondrial oxidative capacity, increased muscle NADH content, and higher muscle free radical release measured in vivo using pMitoTimer reporter.