title: Effects of aerobic training on pyruvate dehydrogenase and pyruvate dehydrogenase kinase in human skeletal muscle.
abstract: This study examined the effects of short- and long-term aerobic training on the stable up-regulation of pyruvate dehydrogenase (PDH) and PDH kinase (PDK) in human skeletal muscle. We hypothesized that 8 weeks, but not 1 week, of aerobic training would increase total PDH (PDHt) and PDK activities compared to pretraining, and this would be detectable at the level of gene transcription (mRNA) and/or gene translation (protein). Resting muscle biopsies were taken before and after 1 and 8 weeks of aerobic cycle exercise training. PDHt and PDK activities, and their respective protein and mRNA expression, did not differ after 1 week of aerobic training. PDHt activity increased 31% after 8 weeks and this may be partially due to a 1.3-fold increase in PDH-E(1)alpha protein expression. PDK activity approximately doubled after 8 weeks of aerobic training and this was attributed to a 1.3-fold increase in PDK2 isoform protein expression. Similar to 1 week, no changes were observed at the mRNA level after 8 weeks of training. These findings suggest that aerobically trained human skeletal muscle has an increased maximal capacity to utilize carbohydrates, evident by increased PDHt, but increased metabolic control sensitivity to pyruvate through increased contribution of PDK2 to total PDK activity.
authors.affiliation: Department Medicine, McMaster University, Hamilton, Ontario, Canada. Email: leblanpj@mcmaster.ca
authors.forename: Paul J
authors.initials: PJ
authors.lastname: LeBlanc
authors.forename: Sandra J
authors.initials: SJ
authors.lastname: Peters
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Tunstall
authors.forename: David
authors.initials: D
authors.lastname: Cameron-Smith
authors.forename: George J F
authors.initials: GJ
authors.lastname: Heigenhauser
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D001642:Bicycling / Q000502:physiology; D001707:Biopsy, Needle; D050260:Carbohydrate Metabolism; D002950:Citrate (si)-Synthase / Q000096:biosynthesis; D042963:Electron Transport Complex II / Q000096:biosynthesis; D003576:Electron Transport Complex IV / Q000096:biosynthesis; D015444:Exercise / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008297:Male; D008931:Mitochondria, Muscle / Q000201:enzymology; D018482:Muscle, Skeletal / Q000201:enzymology*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D021122:Protein Subunits / Q000096:biosynthesis; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D011768:Pyruvate Dehydrogenase Complex / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D013997:Time Factors
chemical_list: C000631430:PDK2 protein, human; D021122:Protein Subunits; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D011768:Pyruvate Dehydrogenase Complex; D012333:RNA, Messenger; D042963:Electron Transport Complex II; D003576:Electron Transport Complex IV; D002950:Citrate (si)-Synthase; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases