Exercise with low glycogen increases PGC-1α gene expression in human skeletal muscle.
Recent studies suggest that carbohydrate restriction can improve the training-induced adaptation of muscle oxidative capacity. However, the importance of low muscle glycogen on the molecular signaling of mitochondrial biogenesis remains unclear. Here, we compare the effects of exercise with low (LG) and normal (NG) glycogen on different molecular factors involved in the regulation of mitochondrial biogenesis. Ten highly trained cyclists (VO(2max) 65 ± 1 ml/kg/min, W max 387 ± 8 W) exercised for 60 min at approximately 64 % VO(2max) with either low [166 ± 21 mmol/kg dry weight (dw)] or normal (478 ± 33 mmol/kg dw) muscle glycogen levels achieved by prior exercise/diet intervention. Muscle biopsies were taken before, and 3 h after, exercise. The mRNA of peroxisome proliferator-activated receptor-γ coactivator-1 was enhanced to a greater extent when exercise was performed with low compared with normal glycogen levels (8.1-fold vs. 2.5-fold increase). Cytochrome c oxidase subunit I and pyruvate dehydrogenase kinase isozyme 4 mRNA were increased after LG (1.3- and 114-fold increase, respectively), but not after NG. Phosphorylation of AMP-activated protein kinase, p38 mitogen-activated protein kinases and acetyl-CoA carboxylase was not changed 3 h post-exercise. Mitochondrial reactive oxygen species production and glutathione oxidative status tended to be reduced 3 h post-exercise. We conclude that exercise with low glycogen levels amplifies the expression of the major genetic marker for mitochondrial biogenesis in highly trained cyclists. The results suggest that low glycogen exercise may be beneficial for improving muscle oxidative capacity.
The Åstrand Laboratory of Work Physiology, GIH, The Swedish School of Sport and Health Sciences, Box 5626, 114 86 Stockholm, Sweden. niklas.psilander@gih.se
Niklas
N
Psilander
Per
P
Frank
Mikael
M
Flockhart
Kent
K
Sahlin
D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D000103:Acetyl-CoA Carboxylase / Q000378:metabolism; D000704:Analysis of Variance; D001642:Bicycling; D001706:Biopsy; D018592:Cross-Over Studies; D050528:Diet, Carbohydrate-Restricted; D003576:Electron Transport Complex IV / Q000235:genetics; D015444:Exercise; D005978:Glutathione / Q000378:metabolism; D006003:Glycogen / Q000172:deficiency / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000235:genetics*; D006801:Humans; D008931:Mitochondria, Muscle / Q000378:metabolism; D063269:Mitochondrial Turnover; D009119:Muscle Contraction; D018384:Oxidative Stress; D010101:Oxygen Consumption; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D052097:Quadriceps Muscle / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013548:Sweden; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics*; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D006360:Heat-Shock Proteins; C000631432:PDK4 protein, human; C486497:PPARGC1A protein, human; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D014157:Transcription Factors; D006003:Glycogen; D003576:Electron Transport Complex IV; C581860:cytochrome c oxidase subunit I, human; D017346:Protein Serine-Threonine Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D055372:AMP-Activated Protein Kinases; D000103:Acetyl-CoA Carboxylase; D005978:Glutathione