Document Detail

Effects of preexercise feeding on markers of satellite cell activation.
MedLine Citation:
PMID:  20216467     Owner:  NLM     Status:  MEDLINE    
PURPOSE: The purpose of this study was to determine if consuming isoenergetic (25 g) doses of carbohydrate or protein versus a noncaloric placebo before conventional resistance training affected the myogenic expression of cell cycle-regulating genes as well as the muscle [DNA] acutely after exercise.
METHODS: Ten untrained men (mean +/- SD: age = 22 +/- 4 yr, body mass = 77.8 +/- 8.3 kg, percent body fat = 17.8 +/- 4.0) participated in three resistance exercise sessions (three sets of 10 repetitions at 80% one-repetition maximum for the bilateral hack squat, leg press, and leg extension exercises) in a crossover fashion, which were preceded by carbohydrate, protein, or placebo ingestion 30 min before training. Presupplement/preexercise and 2- and 6-h postexercise muscle biopsies were obtained during each session and analyzed for fold changes in CDK4, CYCLIN D1, MGF, MYOD, P21(CIP1), and P27(KIP1) messenger RNA expression using real-time reverse transcriptase-polymerase chain reaction as well as muscle [DNA] using cuvette-based fluorometric methods.
RESULTS: Nonparametric statistics were completed, and no conditions x time interaction effects were revealed. Several exercise-mediated responses were found to occur independent of condition: 1) muscle [DNA] increased at 6 h (+40%, P < 0.05), 2) CDK4 expression increased at 6 h (+86%, P < 0.05), 3) MYOD expression increased at 6 h (+98%, P < 0.05), 4) P27(KIP1) expression decreased at 2 h (j35%, P < 0.05) and 6 h (-59%, P < 0.001), and 5) P21(CIP1) expression substantially increased 2 and 6 h postexercise (+1.250% and +4.670%, respectively, P < 0.001).
CONCLUSIONS: The tandem DNA and cell cycle regulator gene expression analyses provide preliminary evidence to suggest that satellite cell activation and proliferation may be occurring at early post-exercise time points after a conventional resistance exercise bout, a phenomenon that may seemingly be independent of preexercise macronutrient ingestion.
Michael D Roberts; Vincent J Dalbo; Scott E Hassell; Ryan Brown; Chad M Kerksick
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Publication Detail:
Type:  Controlled Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  42     ISSN:  1530-0315     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  2010 Oct 
Date Detail:
Created Date:  2010-09-27     Completed Date:  2011-01-13     Revised Date:  2012-06-25    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1861-9     Citation Subset:  IM; S    
Health and Exercise Science Department, University of Oklahoma, Norman, OK 73019-6081, USA.
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MeSH Terms
Biological Markers / metabolism
Cyclin D1 / analysis
Cyclin-Dependent Kinase 4 / analysis
Cyclin-Dependent Kinase Inhibitor p21 / analysis
Cyclin-Dependent Kinase Inhibitor p27
Eating / physiology*
Exercise / physiology*
Gene Expression / physiology
Intracellular Signaling Peptides and Proteins / analysis
Muscle Proteins / metabolism
Muscle, Skeletal / metabolism
MyoD Protein / analysis
Resistance Training
STAT5 Transcription Factor / analysis
Satellite Cells, Skeletal Muscle / metabolism,  physiology*
Tumor Suppressor Proteins / analysis
Young Adult
Reg. No./Substance:
0/Biological Markers; 0/CDKN1A protein, human; 0/CDKN1B protein, human; 0/Cyclin-Dependent Kinase Inhibitor p21; 0/Intracellular Signaling Peptides and Proteins; 0/Muscle Proteins; 0/MyoD Protein; 0/STAT5 Transcription Factor; 0/STAT5A protein, human; 0/Tumor Suppressor Proteins; 136601-57-5/Cyclin D1; 147604-94-2/Cyclin-Dependent Kinase Inhibitor p27; EC protein, human; EC Kinase 4

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

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