| Lactate kinetics in exercising Thoroughbred horses: regulation of turnover rate in plasma. | |
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MedLine Citation:
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PMID: 3425768 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Plasma lactate turnover rate of Thoroughbred racehorses was measured by bolus injection of [U-14C]lactate at rest and two levels of submaximal treadmill exercise (3-4 m/s trot, 6% incline, and 6.5 m/s horizontal canter). Our goals were 1) to determine the relative effects of changes in cardiac output and in plasma lactate concentration on turnover rate [using cardiac output data from Weber et al. (28)] and 2) to assess the importance of lactate as a metabolic fuel in a trained animal athlete. Lactate turnover rates were 9.3 mumol.min-1.kg-1 (rest), 75.9 mumol.min-1.kg-1 at the beginning of the trot protocol [45% maximum O2 uptake (VO2max)], 50.3 mumol.min-1.kg-1 later in the same protocol (50% VO2max), and 66.1 mumol.min-1.kg-1 during the canter protocol (55% VO2max). Both changes in cardiac output and in plasma lactate concentration had a significant effect on turnover rate. Variation in plasma lactate fluxes of Thoroughbreds during exercise follows the standard mammalian pattern, but this substrate only plays a minor role as an oxidizable fuel in horses. The oxidation of plasma lactate accounts for less than 5% of metabolic rate (VO2) during submaximal work. Adjustments in cardiac output and in metabolite concentration represent, respectively, the coarse and fine controls for the regulation of plasma metabolite turnover rate. |
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Authors:
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J M Weber; W S Parkhouse; G P Dobson; J C Harman; D H Snow; P W Hochachka |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: The American journal of physiology Volume: 253 ISSN: 0002-9513 ISO Abbreviation: Am. J. Physiol. Publication Date: 1987 Dec |
Date Detail:
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Created Date: 1988-01-28 Completed Date: 1988-01-28 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 0370511 Medline TA: Am J Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: R896-903 Citation Subset: IM |
Affiliation:
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Physiology Unit, Animal Health Trust, Newmarket, Suffolk, United Kingdom. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Carbohydrate Metabolism Horses / blood, physiology* Kinetics Lactates / blood* Lactic Acid Metabolic Clearance Rate Physical Exertion* Reference Values |
| Chemical | |
Reg. No./Substance:
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0/Lactates; 50-21-5/Lactic Acid |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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