Heat stress enhances mTOR signaling after resistance exercise in human skeletal muscle

Ryo Kakigi; Hisashi Naito; Yuji Ogura; Hiroyuki Kobayashi; Norio Saga; Noriko Ichinoseki-Sekine; Toshinori Yoshihara; Shizuo Katamoto

doi:10.1007/s12576-010-0130-y

Heat stress enhances mTOR signaling after resistance exercise in human skeletal muscle

J Physiol Sci. 2011 Mar;61(2):131-40. doi: 10.1007/s12576-010-0130-y. Epub 2011 Jan 11.

Authors

Ryo Kakigi¹, Hisashi Naito, Yuji Ogura, Hiroyuki Kobayashi, Norio Saga, Noriko Ichinoseki-Sekine, Toshinori Yoshihara, Shizuo Katamoto

Affiliation

¹ Department of Exercise Physiology, Graduate School of Health and Sports Science, Juntendo University, Inzai, Chiba, 270-1695, Japan.

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.

Publication types

Randomized Controlled Trial
Research Support, Non-U.S. Gov't

MeSH terms

3-Phosphoinositide-Dependent Protein Kinases
Adaptor Proteins, Signal Transducing / metabolism
Cell Cycle Proteins
Cross-Over Studies
Exercise / physiology*
Extracellular Signal-Regulated MAP Kinases / metabolism
Heat-Shock Response / physiology*
Hot Temperature
Humans
MAP Kinase Signaling System
Male
Muscle, Skeletal / enzymology
Muscle, Skeletal / metabolism*
Phosphoproteins / metabolism
Phosphorylation
Protein Serine-Threonine Kinases / metabolism
Proto-Oncogene Proteins c-akt / metabolism
Resistance Training*
Ribosomal Protein S6 / metabolism
Ribosomal Protein S6 Kinases, 90-kDa
Signal Transduction
Sirolimus / pharmacology
TOR Serine-Threonine Kinases / metabolism*
Young Adult
p38 Mitogen-Activated Protein Kinases / metabolism

Substances

Adaptor Proteins, Signal Transducing
Cell Cycle Proteins
EIF4EBP1 protein, human
Phosphoproteins
Ribosomal Protein S6
MTOR protein, human
3-Phosphoinositide-Dependent Protein Kinases
Protein Serine-Threonine Kinases
Proto-Oncogene Proteins c-akt
RPS6KA1 protein, human
Ribosomal Protein S6 Kinases, 90-kDa
TOR Serine-Threonine Kinases
Extracellular Signal-Regulated MAP Kinases
p38 Mitogen-Activated Protein Kinases
Sirolimus