| Alanine kinetics in humans during low-intensity exercise. | |
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MedLine Citation:
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PMID: 8183099 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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There is little doubt that pyruvate contributes to the increased alanine flux in exercise, but the role of protein breakdown is less clear. To quantify the relative contributions of pyruvate and protein breakdown to the increase in alanine flux observed in exercise, we used a primed, constant infusion of 15N-alanine and 1-13C-lactate. The rate of appearance of alanine, the de novo synthesis of alanine, and rate of alanine release from protein breakdown were determined in five healthy subjects at rest and during exercise. The exercise was performed for 120 min on a treadmill at 45% of the subject's VO2max. The total rate of appearance of alanine, calculated with the 15N-alanine tracer, increased significantly during exercise from 4.9 +/- 0.5 to 7.9 +/- 0.9 mumol.kg-1. The amount of alanine derived from pyruvate also significantly increased during exercise (3.2 +/- 0.3 vs 4.5 +/- 0.7), but the proportion of the total decreased from 65% at rest to 57% during exercise (statistically significant, P < 0.05). Consequently, the alanine derived from protein breakdown significantly increased (1.7 +/- 0.5 vs 3.4 +/- 0.8) and was also increased as percent of total alanine flux. Thus, we conclude that during low-intensity exercise, whole body protein catabolism is accelerated. |
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Authors:
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F Carraro; A Naldini; J M Weber; R R Wolfe |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Medicine and science in sports and exercise Volume: 26 ISSN: 0195-9131 ISO Abbreviation: Med Sci Sports Exerc Publication Date: 1994 Mar |
Date Detail:
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Created Date: 1994-06-15 Completed Date: 1994-06-15 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 8005433 Medline TA: Med Sci Sports Exerc Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 348-53 Citation Subset: IM; S |
Affiliation:
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Shriners Burns Institute, Department of Surgery, University of Texas Medical Branch at Galveston 77550. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adult Alanine / biosynthesis*, blood Exercise / physiology* Humans Lactates / blood Lactic Acid Male |
| Grant Support | |
ID/Acronym/Agency:
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DK 38010/DK/NIDDK NIH HHS; MO1-RR00073/RR/NCRR NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Lactates; 50-21-5/Lactic Acid; 56-41-7/Alanine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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