| Evidence of separate pathways for lactate uptake and release by the perfused rat heart. | |
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MedLine Citation:
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PMID: 11551857 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The simultaneous release and uptake of lactate by the heart has been observed both in vivo and ex vivo; however, the pathways underlying these observations have not been satisfactorily explained. Consequently, the purpose of this study was to test the hypothesis that hearts release lactate from glycolysis while simultaneously taking up exogenous lactate. Therefore, we determined the effects of fatty acids and diabetes on the regulation of lactate uptake and release. Hearts from control and 1-wk diabetic animals were perfused with 5 mM glucose, 0.5 mM [3-(13)C]lactate, and 0, 0.1, 0.32, or 1.0 mM palmitate. Parameters measured include perfusate lactate concentrations, fractional enrichment, and coronary flow rates, which enabled the simultaneous, but independent, measurements of the rates of 1) uptake of exogenous [(13)C]lactate and 2) efflux of unlabeled lactate from metabolism of glucose. Although the rates of lactate uptake and efflux were both similarly inhibited by the addition of palmitate, (i.e., the ratio of lactate uptake to efflux remained constant), the ratio of lactate uptake to efflux was significantly higher in the controls compared with the diabetic group (1.00 +/- 0.14 vs. 0.50 +/- 0.07, P < 0.002). These data, combined with heterogeneous (13)C enrichment of tissue lactate, pyruvate, and alanine, suggest that glycolytically derived lactate production and oxidation of exogenous lactate operate as functionally separate metabolic pathways. These results are consistent with the concept of an intracellular lactate shuttle. |
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Authors:
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J C Chatham; C Des Rosiers; J R Forder |
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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: American journal of physiology. Endocrinology and metabolism Volume: 281 ISSN: 0193-1849 ISO Abbreviation: Am. J. Physiol. Endocrinol. Metab. Publication Date: 2001 Oct |
Date Detail:
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Created Date: 2001-09-11 Completed Date: 2001-10-18 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 100901226 Medline TA: Am J Physiol Endocrinol Metab Country: United States |
Other Details:
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Languages: eng Pagination: E794-802 Citation Subset: IM |
Affiliation:
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Division of Magnetic Resonance Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA. jchatham@mri.uab.edu |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Alanine
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metabolism Animals Carbon Isotopes Diabetes Mellitus, Experimental / metabolism*, physiopathology Glucose / metabolism Heart / physiology*, physiopathology Lactates / metabolism* Magnetic Resonance Spectroscopy Male Models, Biological Myocardial Contraction Myocardium / metabolism* Palmitic Acid / metabolism Perfusion Pyruvates / metabolism Rats Rats, Sprague-Dawley Reference Values |
| Grant Support | |
ID/Acronym/Agency:
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HL-48789/HL/NHLBI NIH HHS; HL-67464/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Carbon Isotopes; 0/Lactates; 0/Pyruvates; 50-99-7/Glucose; 56-41-7/Alanine; 57-10-3/Palmitic Acid |
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