PMID- 19589955
OWN - NLM
STAT- MEDLINE
DCOM- 20100113
LR  - 20211020
IS  - 1522-1601 (Electronic)
IS  - 8750-7587 (Print)
IS  - 0161-7567 (Linking)
VI  - 107
IP  - 5
DP  - 2009 Nov
TI  - Translational signaling responses preceding resistance training-mediated myofiber 
      hypertrophy in young and old humans.
PG  - 1655-62
LID - 10.1152/japplphysiol.91234.2008 [doi]
AB  - While skeletal muscle protein accretion during resistance training (RT)-mediated 
      myofiber hypertrophy is thought to result from upregulated translation initiation 
      signaling, this concept is based on responses to a single bout of unaccustomed 
      resistance exercise (RE) with no measure of hypertrophy across RT. Further, aging 
      appears to affect acute responses to RE, but whether age differences in 
      responsiveness persist during RT leading to impaired RT adaptation is unclear. We 
      therefore tested whether muscle protein fractional synthesis rate (FSR) and 
      Akt/mammalian target of rapamycin (mTOR) signaling in response to unaccustomed RE 
      differed in old vs. young adults, and whether age differences in acute 
      responsiveness were associated with differences in muscle hypertrophy after 16 wk 
      of RT. Fifteen old and 21 young adult subjects completed the 16-wk study. The 
      phosphorylation states of Akt, S6K1, ribosomal protein S6 (RPS6), eukaryotic 
      initiation factor 4E (eIF4E) binding protein (4EBP1), eIF4E, and eIF4G were all 
      elevated (23-199%) 24 h after a bout of unaccustomed RE. A concomitant 62% 
      increase in FSR was found in a subset (6 old, 8 young). Age x time interaction 
      was found only for RPS6 phosphorylation (+335% in old subjects only), while there 
      was an interaction trend (P = 0.084) for FSR (+96% in young subjects only). After 
      16 wk of RT, gains in muscle mass, type II myofiber size, and voluntary strength 
      were similar in young and old subjects. In conclusion, at the level of 
      translational signaling, we found no evidence of impaired responsiveness among 
      older adults, and for the first time, we show that changes in translational 
      signaling after unaccustomed RE were associated with substantial muscle protein 
      accretion (hypertrophy) during continued RT.
FAU - Mayhew, David L
AU  - Mayhew DL
AD  - UAB Dept. of Physiology, 966 McCallum Basic Health Sciences Bldg., 1530 3rd Ave. 
      South, Birmingham, AL 35294-0005, USA.
FAU - Kim, Jeong-Su
AU  - Kim JS
FAU - Cross, James M
AU  - Cross JM
FAU - Ferrando, Arny A
AU  - Ferrando AA
FAU - Bamman, Marcas M
AU  - Bamman MM
LA  - eng
GR  - R01 AG017896/AG/NIA NIH HHS/United States
GR  - M01-RR-00032/RR/NCRR NIH HHS/United States
GR  - F30-AG-031623/AG/NIA NIH HHS/United States
GR  - R01-AG-017896/AG/NIA NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, U.S. Gov't, Non-P.H.S.
DEP - 20090709
PL  - United States
TA  - J Appl Physiol (1985)
JT  - Journal of applied physiology (Bethesda, Md. : 1985)
JID - 8502536
RN  - 0 (Muscle Proteins)
SB  - IM
MH  - Adolescent
MH  - Adult
MH  - Aged
MH  - Aged, 80 and over
MH  - Female
MH  - Humans
MH  - Hypertrophy/physiopathology
MH  - Male
MH  - Middle Aged
MH  - Muscle Proteins/*metabolism
MH  - Muscle, Skeletal/*metabolism/*pathology
MH  - Protein Modification, Translational
MH  - Resistance Training/*adverse effects
MH  - *Signal Transduction
MH  - Young Adult
PMC - PMC2777794
EDAT- 2009/07/11 09:00
MHDA- 2010/01/14 06:00
PMCR- 2010/11/01
CRDT- 2009/07/11 09:00
PHST- 2009/07/11 09:00 [entrez]
PHST- 2009/07/11 09:00 [pubmed]
PHST- 2010/01/14 06:00 [medline]
PHST- 2010/11/01 00:00 [pmc-release]
AID - 91234.2008 [pii]
AID - JAPPL-91234-2008 [pii]
AID - 10.1152/japplphysiol.91234.2008 [doi]
PST - ppublish
SO  - J Appl Physiol (1985). 2009 Nov;107(5):1655-62. doi: 
      10.1152/japplphysiol.91234.2008. Epub 2009 Jul 9.