PPARGC1A and Impaired glucose tolerance: To determine if the attenuation of mitochondrial function is essential for the development of impaired glucose tolerance and insulin resistance in A1+/-s, we performed TEM analysis for the morphology of mitochondria of aged WTs (Fig 6C) and A1+/-s (Fig 6D) that had been administered ALA for 1 wk, and examined mitochondrial DNA levels and PGC1α expression in the skeletal muscle of aged A1+/-s that were administered ALA for 1 wk and for 6 wks (Fig 6I and 6J).