Training induced improvements in aerobic capacity can occur independent of PGC‐1[alpha] in aging human skeletal muscle

Abstract

The purpose of this investigation was to elucidate the molecular adaptations in skeletal muscle that occur with aerobic exercise training in elderly individuals. Muscle biopsies were obtained from the vastus lateralis of nine old women (70±2y) to determine basal mRNA and/or protein content of factors involved in mitochondrial biogenesis (TFAM, PGC‐1α, COX IV) before and after 12‐weeks of aerobic training on a cycle ergometer. Post training biopsies occurred ~48 hours after the last exercise session in order to assess steady state levels of select mRNA and/or protein. Whole body aerobic capacity increased (P<0.05) 30±9% and COX IV protein, a marker of mitochondrial content, was elevated (P<0.05) 33±7% after training. Interestingly, aerobic training did not alter the basal gene expression of PGC‐1α and TFAM. However, PGC‐1α protein content was reduced (P<0.05) 20±5% after aerobic training. These data suggest that increased basal levels of PGC‐1α are not necessary for the improvements in whole body and skeletal muscle oxidative capacity with exercise training in elderly women.Supported by grants NIH (AG032127) and NASA (NJ06HF59G)