Document Detail


Lactate transport in rat sarcolemmal vesicles after a single bout of submaximal exercise.
MedLine Citation:
PMID:  10961513     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We investigated the effects of a single bout of non-exhaustive exercise (25 m x min(-1), 10% grade, for 30 min) on the initial rates of lactate uptake in rat skeletal muscle sarcolemmal vesicles and the monocarboxylate transporter 1 (MCT1) content in isolated hindlimb muscles in relation to the exercise-induced oxidative stress. The exercise led to a decrease in red gastrocnemius and red vastus lateralis muscle glycogen content by 74% and 83%, respectively, and an increase in blood lactate concentration from 1.67 +/- 0.15 to 3.44 +/- 0.47 mM (p < 0.05). Initial rates of lactate uptake were measured in zero-trans conditions, at pH 7.4, for 1, 10, 30 and 100 mM external lactate concentrations. Lactate transport capacity was significantly decreased at 1 mM in the exercised group (p < 0.05), while a non-significant trend towards an increase was observed at 10, 30 and 100 mM. We failed to obtain any change in soleus, red tibialis anterior and white gastrocnemius muscle MCT1 content (p>0.05), and no evidence of exercise-induced oxidative stress in terms of muscle malondialdehyde content and glutathione peroxidase and superoxide dismutase activities was observed after the 30 min exercise bout. These results indicate that a single bout of submaximal exercise, which did not induce an increase in muscle MCT1 content and apparent oxidative stress, decreased lactate transport capacity at low physiological concentration. Although the changes are small and independent of a MCT1-facilitated lactate transport regulation, we suggest that another MCT isoform with different kinetic properties from MCT1 could be present in the sarcolemma and responsible for lactate exchange alterations.
Authors:
N Eydoux; H Dubouchaud; G Py; P Granier; C Préfaut; J Mercier
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  International journal of sports medicine     Volume:  21     ISSN:  0172-4622     ISO Abbreviation:  Int J Sports Med     Publication Date:  2000 Aug 
Date Detail:
Created Date:  2000-12-04     Completed Date:  2000-12-28     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  8008349     Medline TA:  Int J Sports Med     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  393-9     Citation Subset:  IM    
Affiliation:
Laboratoire de Physiologie des Interactions, Hôpital Arnaud de Villeneuve, Montpellier, France. physio34@aol.com
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MeSH Terms
Descriptor/Qualifier:
Animals
Biological Transport
Hindlimb / physiology
Lactic Acid / metabolism*
Male
Muscle, Skeletal / cytology,  physiology*
Oxidative Stress
Physical Conditioning, Animal / physiology*
Rats
Rats, Wistar
Sarcolemma / physiology*
Chemical
Reg. No./Substance:
50-21-5/Lactic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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