title: Heat stress enhances mTOR signaling after resistance exercise in human skeletal muscle.
abstract: This study investigated the effect of heat stress (HS) on mammalian target of rapamycin (mTOR) signaling involved in translation initiation after resistance exercise in human skeletal muscle. Eight young male subjects performed four sets of six maximal repetitions of knee extension exercises, with or without HS, in a randomized crossover design. HS was applied to the belly of the vastus lateralis by using a microwave therapy unit prior to and during exercise. Muscle biopsies were taken from the vastus lateralis before, immediately after, and 1 h after exercise. HS significantly increased the phosphorylation of Akt/PKB, mTOR, and ribosomal protein S6 at 1 h after exercise (P < 0.05), and the 4E-BP1 phosphorylation level, which had initially decreased with exercise, had recovered by 1 h after exercise with HS. In addition, the phosphorylation of ribosomal S6 kinase 1 was significantly increased immediately after exercise with HS (P < 0.05). These results indicate that HS enhances mTOR signaling after resistance exercise in human skeletal muscle.
authors.affiliation: Department of Exercise Physiology, Graduate School of Health and Sports Science, Juntendo University, Inzai, Chiba, 270-1695, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Kakigi
authors.forename: Hisashi
authors.initials: H
authors.lastname: Naito
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ogura
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Norio
authors.initials: N
authors.lastname: Saga
authors.forename: Noriko
authors.initials: N
authors.lastname: Ichinoseki-Sekine
authors.forename: Toshinori
authors.initials: T
authors.lastname: Yoshihara
authors.forename: Shizuo
authors.initials: S
authors.lastname: Katamoto
mesh_terms: D064413:3-Phosphoinositide-Dependent Protein Kinases; D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D018797:Cell Cycle Proteins; D018592:Cross-Over Studies; D015444:Exercise / Q000502:physiology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D018869:Heat-Shock Response / Q000502:physiology*; D006358:Hot Temperature; D006801:Humans; D020935:MAP Kinase Signaling System; D008297:Male; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D055070:Resistance Training; D038601:Ribosomal Protein S6 / Q000378:metabolism; D038744:Ribosomal Protein S6 Kinases, 90-kDa; D015398:Signal Transduction; D020123:Sirolimus / Q000494:pharmacology; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*; D055815:Young Adult; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; C087000:EIF4EBP1 protein, human; D010750:Phosphoproteins; D038601:Ribosomal Protein S6; C546842:MTOR protein, human; D064413:3-Phosphoinositide-Dependent Protein Kinases; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; C069329:RPS6KA1 protein, human; D038744:Ribosomal Protein S6 Kinases, 90-kDa; D058570:TOR Serine-Threonine Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D020123:Sirolimus