PGC‐1α is required for exercise‐induced mitochondrial biogenesis, but not fiber type transformation, in skeletal muscle

Abstract

Endurance exercise training promotes mitochondrial biogenesis and fiber type transformation in skeletal muscle. Accumulating evidence suggests that peroxisome proliferator‐activated receptor γ coactivator‐1α (PGC‐1α) play a pivotal role since endurance exercise induces PGC‐1α expression, overexpression of PGC‐1α in skeletal muscle results in enhanced mitochondrial biogenesis and increased oxidative myofibers, whereas genetic disruption of the Pgc‐1α gene results in opposite changes. However, it has not been shown that PGC‐1α is required for exercise‐induced skeletal muscle adaptation, and its precise functional role is not clear. Here, mice with skeletal muscle‐specific knockout of the Pgc‐1α gene showed attenuated cytochrome oxidase IV (COX IV) and cytochrome c (Cyt c) expression, but normal induction of myoglobin expression and type IIb‐to‐IIa fiber type transformation, in response to voluntary running exercise. These findings genetically separated the functional role of PGC‐1α in exercise‐induced mitochondrial biogenesis from that in fiber type transformation.