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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
6 Pt 1
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pubmed:dateCreated |
1988-1-27
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pubmed:abstractText |
An isolated single rat hindlimb muscle preparation was used to examine leucine metabolism during steady-state conditions as a function of metabolic rate (VO2) and leucine concentration. The rates of muscle leucine uptake and leucine oxidation (measured as alpha-decarboxylation) were dependent on leucine delivery. At a physiological leucine concentration (0.1 mM), leucine uptake and alpha-ketoisocaproic acid (KIC) release during rest was 12.8 +/- 0.4 and 1.86 +/- 0.06 nmol.min-1.g-1 g, respectively. Leucine oxidation was 2.35 +/- 0.11 nmol.min-1.g-1 (n = 24) and if fully oxidized could account for only 3-4% of the resting VO2. This fraction was reduced to approximately 1% during contractions. The rate of leucine oxidation progressively increased, up to two to three times above rest (6-7 nmol.min-1.g-1), during contractions of graded frequency (7.5, 15, 30, 45, and 60 tetani/min) in a manner related to the eightfold increase in VO2 of the mixed fiber muscle. The fraction of muscle leucine uptake that was transaminated (i.e., leucine decarboxylation + KIC release) increased from 33% at rest to approximately 60% during contractions. The increase in leucine oxidation during contractions was probably primarily due to the high oxidative fast-twitch, red muscle mass, whose VO2 was estimated to increase up to 24-fold above rest. On the basis of our observed rates of muscle leucine alpha-decarboxylation, it is reasonable to attribute the rates of whole-body leucine oxidation of nontrained individuals during exercise to leucine oxidation by the working muscle.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Adenosine Triphosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Glycogen,
http://linkedlifedata.com/resource/pubmed/chemical/Lactates,
http://linkedlifedata.com/resource/pubmed/chemical/Leucine,
http://linkedlifedata.com/resource/pubmed/chemical/Phosphocreatine
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pubmed:status |
MEDLINE
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pubmed:month |
Dec
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pubmed:issn |
0002-9513
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
253
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
E636-47
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:3425710-Adenosine Triphosphate,
pubmed-meshheading:3425710-Animals,
pubmed-meshheading:3425710-Glycogen,
pubmed-meshheading:3425710-Lactates,
pubmed-meshheading:3425710-Leucine,
pubmed-meshheading:3425710-Male,
pubmed-meshheading:3425710-Muscle Contraction,
pubmed-meshheading:3425710-Muscles,
pubmed-meshheading:3425710-Oxidation-Reduction,
pubmed-meshheading:3425710-Oxygen Consumption,
pubmed-meshheading:3425710-Perfusion,
pubmed-meshheading:3425710-Phosphocreatine,
pubmed-meshheading:3425710-Rats
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pubmed:year |
1987
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pubmed:articleTitle |
Leucine metabolism in perfused rat skeletal muscle during contractions.
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pubmed:affiliation |
Department of Physiology, State University of New York Health Science Center at Syracuse 13210.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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