| Intra- and extra-cellular lactate shuttles. | |
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MedLine Citation:
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PMID: 10776898 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The "lactate shuttle hypothesis" holds that lactate plays a key role in the distribution of carbohydrate potential energy that occurs among various tissue and cellular compartments such as between: cytosol and mitochondria, muscle and blood, blood and muscle, active and inactive muscles, white and red muscles, blood and heart, arterial blood and liver, liver and other tissues such as exercising muscle, intestine and portal blood, portal blood and liver, zones of the liver, and skin and blood. Studies on resting and exercising humans indicate that most lactate (75-80%) is disposed of through oxidation, with much of the remainder converted to glucose and glycogen. Lactate transport across cellular membranes occurs by means of facilitated exchange along pH and concentration gradients involving a family of lactate transport proteins, now called monocarboxylate transporters (MCTs). Current evidence is that muscle and other cell membrane lactate transporters are abundant with characteristics of high Km and Vmax. There appears to be long-term plasticity in the number of cell membrane transporters, but short-term regulation by allosteric modulation or phosphorylation is not known. In addition to cell membranes, mitochondria also contain monocarboxylate transporters (mMCT) and lactic dehydrogenase (mLDH). Therefore, mitochondrial monocarboxylate uptake and oxidation, rather than translocation of transporters to the cell surfaces, probably regulate lactate flux in vivo. Accordingly, the "lactate shuttle" hypothesis has been modified to include a new, intracellular component involving cytosolic to mitochondrial exchange. The intracellular lactate shuttle emphasizes the role of mitochondrial redox in the oxidation and disposal of lactate during exercise and other conditions. |
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Authors:
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G A Brooks |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, P.H.S.; Review |
Journal Detail:
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Title: Medicine and science in sports and exercise Volume: 32 ISSN: 0195-9131 ISO Abbreviation: Med Sci Sports Exerc Publication Date: 2000 Apr |
Date Detail:
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Created Date: 2000-06-28 Completed Date: 2000-06-28 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: 790-9 Citation Subset: IM; S |
Affiliation:
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Department of Integrative Biology, University of California, Berkeley 94720-3140, USA. GBrooks@Socrates.Berkeley.Edu |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Carrier Proteins / physiology* Exercise / physiology Glucose / biosynthesis Humans Lactic Acid / metabolism* Muscles / metabolism Sarcolemma / metabolism |
| Grant Support | |
ID/Acronym/Agency:
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AR42906/AR/NIAMS NIH HHS; DK19577/DK/NIDDK NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Carrier Proteins; 50-21-5/Lactic Acid; 50-99-7/Glucose |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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