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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
6
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pubmed:dateCreated |
1986-8-18
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pubmed:abstractText |
ATP turnover and glycolytic rates during isometric contraction in humans have been investigated. Subjects contracted the knee extensor muscles at two-thirds maximal voluntary force to fatigue (mean +/- SE, 53 +/- 4 s). Biopsies were obtained before and after exercise and analyzed for high-energy phosphates and glycogenolytic-glycolytic intermediates. Total ATP turnover was 190 +/- 7 mmol/kg dry muscle, whereas the average turnover rate was 3.7 +/- 0.2 mmol . kg dry muscle-1 . S-1. The average ATP turnover rate was positively correlated with the percentage of fast-twitch fibers in the postexercise biopsy (r = 0.71; P less than 0.05) and negatively correlated with contraction duration to fatigue (r = -0.88; P less than 0.05). At fatigue, phosphocreatine ranged from 1 to 11 mmol/kg dry muscle (86-99% depletion of value at rest), whereas lactate ranged from 59 to 101. The mean glycolytic rate was 0.83 +/- 0.05 mmol . kg dry muscle-1 . S-1 and was positively correlated with the rate of glucose 6-phosphate accumulation (r = 0.83; P less than 0.05). It is concluded that a major determinant of the ATP turnover rate is the muscle fiber composition, which is probably explained by a higher turnover rate in fast-twitch fibers; fatigue is more closely related to a low phosphocreatine content than to a high lactate content; and the increase in prephosphofructokinase intermediates is important for stimulating glycolysis during contraction.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Jun
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pubmed:issn |
8750-7587
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
60
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
1839-42
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:3722052-Adenosine Triphosphate,
pubmed-meshheading:3722052-Adolescent,
pubmed-meshheading:3722052-Adult,
pubmed-meshheading:3722052-Energy Metabolism,
pubmed-meshheading:3722052-Female,
pubmed-meshheading:3722052-Glucose,
pubmed-meshheading:3722052-Glycogen,
pubmed-meshheading:3722052-Glycolysis,
pubmed-meshheading:3722052-Humans,
pubmed-meshheading:3722052-Isometric Contraction,
pubmed-meshheading:3722052-Male,
pubmed-meshheading:3722052-Muscle Contraction,
pubmed-meshheading:3722052-Muscles,
pubmed-meshheading:3722052-Phosphates
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pubmed:year |
1986
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pubmed:articleTitle |
Muscle ATP turnover rate during isometric contraction in humans.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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