Exercise-induced expression of peroxisome proliferator-activated receptor γ coactivator-1α isoforms in skeletal muscle of endurance-trained males

The aim of the present study was to investigate the effect of acute aerobic exercise on the expression of PGC-1 alpha transcript variants in human skeletal muscle. Seven endurance-trained athletes performed a 90-min cycling test (62 % of o(2max)). At resting state, the levels of N-truncated (NT)-PGC-1 alpha and PGC-1 alpha exon 1a-derived transcripts were significantly higher (> 20-fold; P < 0.05) than those of PGC-1 alpha exon 1b- and 1c-derived transcripts. Acute exercise did not change the PGC-1 alpha exon 1a-derived expression level, but it did increase the expression level of NT-PGC-1 alpha mRNAs 6-fold, and the expression levels of PGC-1 alpha exon 1b- and 1c-derived mRNAs > 200-fold (P < 0.05). We conclude that NT-PGC-1 alpha transcript expression in resting muscle and after acute moderate-intensity exercise constituted a significant share of total PGC-1 alpha expression. The exercise led to a higher level of PGC-1 alpha expression from alternative promoters (exon 1b- and 1c-derived mRNA) than from the canonical proximal promoter (exon 1a-derived mRNA).