title: The role of mTOR signalling in the regulation of skeletal muscle mass in a rodent model of resistance exercise.
abstract: Resistance exercise (RE) activates signalling by the mammalian target of rapamycin (mTOR), and it has been suggested that rapamycin-sensitive mTOR signalling controls RE-induced changes in protein synthesis, ribosome biogenesis, autophagy, and the expression of peroxisome proliferator gamma coactivator 1 alpha (PGC-1α). However, direct evidence to support the aforementioned relationships is lacking. Therefore, in this study, we investigated the role of rapamycin-sensitive mTOR in the RE-induced activation of muscle protein synthesis, ribosome biogenesis, PGC-1α expression and hypertrophy. The results indicated that the inhibition of rapamycin-sensitive mTOR could prevent the induction of ribosome biogenesis by RE, but it only partially inhibited the activation of muscle protein synthesis. Likewise, the inhibition of rapamycin-sensitive mTOR only partially blocked the hypertrophic effects of chronic RE. Furthermore, both acute and chronic RE promoted an increase in PGC-1α expression and these alterations were not affected by the inhibition of rapamycin-sensitive mTOR. Combined, the results from this study not only establish that rapamycin-sensitive mTOR plays an important role in the RE-induced activation of protein synthesis and the induction of hypertrophy, but they also demonstrate that additional (rapamycin-sensitive mTOR-independent) mechanisms contribute to these fundamentally important events.
authors: Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan.|Department of Life Sciences, The University of Tokyo, Tokyo, Japan.
authors: Riki
authors: R
authors: Ogasawara
authors: Department of Sport and Health Science, Ritsumeikan University, Kusatsu, Japan.
authors: Satoshi
authors: S
authors: Fujita
authors: Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.
authors: Troy A
authors: TA
authors: Hornberger
authors: Department of Life Sciences, The University of Tokyo, Tokyo, Japan.
authors: Yu
authors: Y
authors: Kitaoka
authors: Department of Sport and Health Science, Ritsumeikan University, Kusatsu, Japan.
authors: Yuhei
authors: Y
authors: Makanae
authors: Department of exercise physiology, Nippon Sport Science University, Tokyo, Japan.
authors: Koichi
authors: K
authors: Nakazato
authors: Department of Life Sciences, The University of Tokyo, Tokyo, Japan.
authors: Ishii
authors: I
authors: Naokata
mesh_terms: D000818:Animals; D017079:Exercise Tolerance / Q000502:physiology*; D008297:Male; D009124:Muscle Proteins / Q000096:biosynthesis; D018482:Muscle, Skeletal / Q000378:metabolism*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D014176:Protein Biosynthesis / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000502:physiology*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*
chemical_list: D009124:Muscle Proteins; C546845:mTOR protein, rat; D058570:TOR Serine-Threonine Kinases