Document Detail

Intake of branched-chain amino acids influences the levels of MAFbx mRNA and MuRF-1 total protein in resting and exercising human muscle.
MedLine Citation:
PMID:  22127230     Owner:  NLM     Status:  MEDLINE    
Resistance exercise and amino acids are two major factors that influence muscle protein turnover. Here, we examined the effects of resistance exercise and branched-chain amino acids (BCAA), individually and in combination, on the expression of anabolic and catabolic genes in human skeletal muscle. Seven subjects performed two sessions of unilateral leg press exercise with randomized supplementation with BCAA or flavored water. Biopsies were collected from the vastus lateralis muscle of both the resting and exercising legs before and repeatedly after exercise to determine levels of mRNA, protein phosphorylation, and amino acid concentrations. Intake of BCAA reduced (P < 0.05) MAFbx mRNA by 30 and 50% in the resting and exercising legs, respectively. The level of MuRF-1 mRNA was elevated (P < 0.05) in the exercising leg two- and threefold under the placebo and BCAA conditions, respectively, whereas MuRF-1 total protein increased by 20% (P < 0.05) only in the placebo condition. Phosphorylation of p70(S6k) increased to a larger extent (∼2-fold; P < 0.05) in the early recovery period with BCAA supplementation, whereas the expression of genes regulating mTOR activity was not influenced by BCAA. Muscle levels of phenylalanine and tyrosine were reduced (13-17%) throughout recovery (P < 0.05) in the placebo condition and to a greater extent (32-43%; P < 0.05) following BCAA supplementation in both resting and exercising muscle. In conclusion, BCAA ingestion reduced MAFbx mRNA and prevented the exercise-induced increase in MuRF-1 total protein in both resting and exercising leg. Further-more, resistance exercise differently influenced MAFbx and MuRF-1 mRNA expression, suggesting both common and divergent regulation of these two ubiquitin ligases.
Marcus Borgenvik; William Apró; Eva Blomstrand
Publication Detail:
Type:  Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't     Date:  2011-11-29
Journal Detail:
Title:  American journal of physiology. Endocrinology and metabolism     Volume:  302     ISSN:  1522-1555     ISO Abbreviation:  Am. J. Physiol. Endocrinol. Metab.     Publication Date:  2012 Mar 
Date Detail:
Created Date:  2012-02-23     Completed Date:  2012-04-13     Revised Date:  2012-08-30    
Medline Journal Info:
Nlm Unique ID:  100901226     Medline TA:  Am J Physiol Endocrinol Metab     Country:  United States    
Other Details:
Languages:  eng     Pagination:  E510-21     Citation Subset:  IM    
The Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden.
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MeSH Terms
Amino Acids / blood,  metabolism
Amino Acids, Branched-Chain / administration & dosage*,  blood,  metabolism
Cross-Over Studies
Dietary Supplements*
Double-Blind Method
Gene Expression Regulation*
Muscle Proteins / genetics,  metabolism*
Protein Processing, Post-Translational
Quadriceps Muscle / metabolism*
RNA, Messenger / metabolism
Resistance Training*
Ribosomal Protein S6 Kinases, 70-kDa / metabolism
SKP Cullin F-Box Protein Ligases / genetics,  metabolism*
Signal Transduction
TOR Serine-Threonine Kinases / metabolism
Ubiquitin-Protein Ligases / genetics,  metabolism*
Reg. No./Substance:
0/Amino Acids; 0/Amino Acids, Branched-Chain; 0/Muscle Proteins; 0/RNA, Messenger; EC protein, human; EC Serine-Threonine Kinases; EC Protein S6 Kinases, 70-kDa; EC protein S6 kinase, 70kD, polypeptide 1; EC protein, human; EC Cullin F-Box Protein Ligases; EC protein, human; EC Ligases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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