| Effect of glycogen availability on human skeletal muscle protein turnover during exercise and recovery. | |
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MedLine Citation:
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PMID: 20489032 Owner: NLM Status: In-Process |
Abstract/OtherAbstract:
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We examined the effect of carbohydrate (CHO) availability on whole body and skeletal muscle protein utilization at rest, during exercise, and during recovery in humans. Six men cycled at approximately 75% peak O(2) uptake (Vo(2peak)) to exhaustion to reduce body CHO stores and then consumed either a high-CHO (H-CHO; 71 + or - 3% CHO) or low-CHO (L-CHO; 11 + or - 1% CHO) diet for 2 days before the trial in random order. After each dietary intervention, subjects received a primed constant infusion of [1-(13)C]leucine and l-[ring-(2)H(5)]phenylalanine for measurements of the whole body net protein balance and skeletal muscle protein turnover. Muscle, breath, and arterial and venous blood samples were obtained at rest, during 2 h of two-legged kicking exercise at approximately 45% of kicking Vo(2peak), and during 1 h of recovery. Biopsy samples confirmed that the muscle glycogen concentration was lower in the L-CHO group versus the H-CHO group at rest, after exercise, and after recovery. The net leg protein balance was decreased in the L-CHO group compared with at rest and compared with the H-CHO condition, which was primarily due to an increase in protein degradation (area under the curve of the phenylalanine rate of appearance: 1,331 + or - 162 micromol in the L-CHO group vs. 786 + or - 51 micromol in the H-CHO group, P < 0.05) but also due to a decrease in protein synthesis late in exercise. There were no changes during exercise in the rate of appearance compared with rest in the H-CHO group. Whole body leucine oxidation increased above rest in the L-CHO group only and was higher than in the H-CHO group. The whole body net protein balance was reduced in the L-CHO group, largely due to a decrease in whole body protein synthesis. These data extend previous findings by others and demonstrate, using contemporary stable isotope methodology, that CHO availability influences the rates of skeletal muscle and whole body protein synthesis, degradation, and net balance during prolonged exercise in humans. |
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Authors:
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Krista R Howarth; Stuart M Phillips; Maureen J MacDonald; Douglas Richards; Natalie A Moreau; Martin J Gibala |
Publication Detail:
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Type: Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't Date: 2010-05-20 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 109 ISSN: 1522-1601 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2010 Aug |
Date Detail:
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Created Date: 2010-08-10 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 431-8 Citation Subset: IM |
Affiliation:
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Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada. |
Export Citation:
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Descriptor/Qualifier:
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| Grant Support | |
ID/Acronym/Agency:
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//Canadian Institutes of Health Research |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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