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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
5
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pubmed:dateCreated |
1991-1-17
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pubmed:abstractText |
1. Using the forearm balance method, together with systemic infusions of L-[ring-2,6-3H]phenylalanine and L-[1-14C]leucine, we examined the effects of infused branched-chain amino acids on whole-body and skeletal muscle amino acid kinetics in 10 postabsorptive normal subjects; 10 control subjects received only saline. 2. Infusion of branched-chain amino acids caused a four-fold rise in arterial branched-chain amino acid levels and a two-fold rise in branched-chain keto acids; significant declines were observed in circulating levels of most other amino acids, including phenylalanine, which fell by 34%. Plasma insulin levels were unchanged from basal levels (8 +/- 1 mu-units/ml). 3. Whole-body phenylalanine flux, an index of proteolysis, was significantly suppressed by branched-chain amino acid infusion (P less than 0.002), and forearm phenylalanine production was also inhibited (P less than 0.03). With branched-chain amino acid infusion total leucine flux rose, with marked increments in both oxidative and non-oxidative leucine disposal (P less than 0.001). Proteolysis, as measured by endogenous leucine production, showed a modest 12% decrease, although this was not significant when compared with saline controls. The net forearm balance of leucine and other branched-chain amino acids changed from a basal net output to a marked net uptake (P less than 0.001) during branched-chain amino acid infusion, with significant stimulation of local leucine disposal. Despite the rise in whole-body non-oxidative leucine disposal, and in forearm leucine uptake and disposal, forearm phenylalanine disposal, an index of muscle protein synthesis, was not stimulated by infusion of branched-chain amino acids. 4. The results suggest that in normal man branched-chain amino acid infusion suppresses skeletal muscle proteolysis independently of any rise of plasma insulin. Muscle branched-chain amino acid uptake rose dramatically in the absence of any apparent increase in muscle protein synthesis, as measured by phenylalanine disposal, or in branched-chain keto acid release. Thus, an increase in muscle branched-chain amino acid concentrations and/or local branched-chain amino acid oxidation must account for the increased disposal of branched-chain amino acids.
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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/Amino Acids, Branched-Chain,
http://linkedlifedata.com/resource/pubmed/chemical/Insulin,
http://linkedlifedata.com/resource/pubmed/chemical/Leucine,
http://linkedlifedata.com/resource/pubmed/chemical/Muscle Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Phenylalanine
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pubmed:status |
MEDLINE
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pubmed:month |
Nov
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pubmed:issn |
0143-5221
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
79
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
457-66
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pubmed:dateRevised |
2011-11-17
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pubmed:meshHeading |
pubmed-meshheading:2174312-Adolescent,
pubmed-meshheading:2174312-Adult,
pubmed-meshheading:2174312-Amino Acids, Branched-Chain,
pubmed-meshheading:2174312-Female,
pubmed-meshheading:2174312-Forearm,
pubmed-meshheading:2174312-Humans,
pubmed-meshheading:2174312-Infusions, Intravenous,
pubmed-meshheading:2174312-Insulin,
pubmed-meshheading:2174312-Kinetics,
pubmed-meshheading:2174312-Leucine,
pubmed-meshheading:2174312-Male,
pubmed-meshheading:2174312-Muscle Proteins,
pubmed-meshheading:2174312-Muscles,
pubmed-meshheading:2174312-Phenylalanine
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pubmed:year |
1990
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pubmed:articleTitle |
Effect of infused branched-chain amino acids on muscle and whole-body amino acid metabolism in man.
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pubmed:affiliation |
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06510.
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pubmed:publicationType |
Journal Article,
Clinical Trial,
Research Support, U.S. Gov't, P.H.S.,
Controlled Clinical Trial
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