PMID- 17569770
OWN - NLM
STAT- MEDLINE
DCOM- 20071220
LR  - 20220410
IS  - 8750-7587 (Print)
IS  - 0161-7567 (Linking)
VI  - 103
IP  - 3
DP  - 2007 Sep
TI  - Blood flow restriction during low-intensity resistance exercise increases S6K1 
      phosphorylation and muscle protein synthesis.
PG  - 903-10
AB  - Low-intensity resistance exercise training combined with blood flow restriction 
      (REFR) increases muscle size and strength as much as conventional resistance 
      exercise with high loads. However, the cellular mechanism(s) underlying the 
      hypertrophy and strength gains induced by REFR are unknown. We have recently 
      shown that both the mammalian target of rapamycin (mTOR) signaling pathway and 
      muscle protein synthesis (MPS) were stimulated after an acute bout of 
      high-intensity resistance exercise in humans. Therefore, we hypothesized that an 
      acute bout of REFR would enhance mTOR signaling and stimulate MPS. We measured 
      MPS and phosphorylation status of mTOR-associated signaling proteins in six young 
      male subjects. Subjects were studied once during blood flow restriction (REFR, 
      bilateral leg extension exercise at 20% of 1 repetition maximum while a pressure 
      cuff was placed on the proximal end of both thighs and inflated at 200 mmHg) and 
      a second time using the same exercise protocol but without the pressure cuff 
      [control (Ctrl)]. MPS in the vastus lateralis muscle was measured by using stable 
      isotope techniques, and the phosphorylation status of signaling proteins was 
      determined by immunoblotting. Blood lactate, cortisol, and growth hormone were 
      higher following REFR compared with Ctrl (P < 0.05). Ribosomal S6 kinase 1 (S6K1) 
      phosphorylation, a downstream target of mTOR, increased concurrently with a 
      decreased eukaryotic translation elongation factor 2 (eEF2) phosphorylation and a 
      46% increase in MPS following REFR (P < 0.05). MPS and S6K1 phosphorylation were 
      unchanged in the Ctrl group postexercise. We conclude that the activation of the 
      mTOR signaling pathway appears to be an important cellular mechanism that may 
      help explain the enhanced muscle protein synthesis during REFR.
FAU - Fujita, Satoshi
AU  - Fujita S
AD  - Department of Internal Medicine, University of Texas Medical Branch, Galveston, 
      Texas, USA. fujita@k.u-tokyo.ac.jp
FAU - Abe, Takashi
AU  - Abe T
FAU - Drummond, Micah J
AU  - Drummond MJ
FAU - Cadenas, Jerson G
AU  - Cadenas JG
FAU - Dreyer, Hans C
AU  - Dreyer HC
FAU - Sato, Yoshiaki
AU  - Sato Y
FAU - Volpi, Elena
AU  - Volpi E
FAU - Rasmussen, Blake B
AU  - Rasmussen BB
LA  - eng
GR  - R01-AR-049877/AR/NIAMS NIH HHS/United States
GR  - S10-RR-16650/RR/NCRR NIH HHS/United States
GR  - M01-RR-00073/RR/NCRR NIH HHS/United States
GR  - R01 AR049877/AR/NIAMS NIH HHS/United States
GR  - P30-AG-024832/AG/NIA NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, Non-U.S. Gov't
DEP - 20070614
PL  - United States
TA  - J Appl Physiol (1985)
JT  - Journal of applied physiology (Bethesda, Md. : 1985)
JID - 8502536
RN  - 0 (Hormones)
RN  - 0 (Muscle Proteins)
RN  - 0 (Peptide Elongation Factor 2)
RN  - 33X04XA5AT (Lactic Acid)
RN  - 47E5O17Y3R (Phenylalanine)
RN  - EC 2.7.- (Protein Kinases)
RN  - EC 2.7.1.1 (MTOR protein, human)
RN  - EC 2.7.11.1 (Proto-Oncogene Proteins c-akt)
RN  - EC 2.7.11.1 (RPS6KA1 protein, human)
RN  - EC 2.7.11.1 (Ribosomal Protein S6 Kinases, 90-kDa)
RN  - EC 2.7.11.1 (TOR Serine-Threonine Kinases)
SB  - IM
EIN - J Appl Physiol. 2008 Apr;104(4):1256
MH  - Adult
MH  - Exercise/*physiology
MH  - Hormones/blood
MH  - Humans
MH  - Hydrogen-Ion Concentration
MH  - Lactic Acid/blood
MH  - Leg/*blood supply
MH  - Male
MH  - Muscle Proteins/*biosynthesis
MH  - Peptide Elongation Factor 2/metabolism
MH  - Phenylalanine/metabolism
MH  - Phosphorylation
MH  - Protein Kinases/*metabolism
MH  - Proto-Oncogene Proteins c-akt/metabolism
MH  - Regional Blood Flow/physiology
MH  - Ribosomal Protein S6 Kinases, 90-kDa/*metabolism
MH  - Signal Transduction/physiology
MH  - TOR Serine-Threonine Kinases
EDAT- 2007/06/16 09:00
MHDA- 2007/12/21 09:00
CRDT- 2007/06/16 09:00
PHST- 2007/06/16 09:00 [pubmed]
PHST- 2007/12/21 09:00 [medline]
PHST- 2007/06/16 09:00 [entrez]
AID - 00195.2007 [pii]
AID - 10.1152/japplphysiol.00195.2007 [doi]
PST - ppublish
SO  - J Appl Physiol (1985). 2007 Sep;103(3):903-10. doi: 
      10.1152/japplphysiol.00195.2007. Epub 2007 Jun 14.