Document Detail

Potassium fluxes in contracting human skeletal muscle and red blood cells.
MedLine Citation:
PMID:  9887193     Owner:  NLM     Status:  MEDLINE    
The present study examined K+ fluxes in red blood cells and muscle during muscle contractions. Seven subjects performed two-legged submaximal knee-extensor exercise for 30 min. After 10 min of leg exercise (L1), intense arm exercise was also performed for 10 min (L2+A). Plasma epinephrine and norepinephrine concentrations were higher (P < 0.05) in L2+A compared with L1. Arterial plasma K+ at the end of L2+A was higher than in L1 (5.6 vs. 4.4 mM, P < 0.05) and returned to the L1 level on cessation of arm exercise. A net K+ release of 0.16 mmol/min from the active legs during L1 was turned to a net K+ uptake of 0.79 mmol/min during L2+A. Both arterial and venous red blood cell K+-to-hemoglobin ratios were constant during exercise. The present data suggest that contracting muscle can take up K+ probably by a combination of K+ and hormone activation of the Na+-K+ pump. Furthermore, changes in red blood cell K+ concentrations during muscle activity appear to be due to water movements and not transmembrane fluxes of K+.
C Juel; Y Hellsten; B Saltin; J Bangsbo
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of physiology     Volume:  276     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1999 Jan 
Date Detail:
Created Date:  1999-03-05     Completed Date:  1999-03-05     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  R184-8     Citation Subset:  IM    
Copenhagen Muscle Research Centre, August Krogh Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark.
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MeSH Terms
Catecholamines / blood
Erythrocyte Volume / physiology
Erythrocytes / metabolism*
Hydrogen-Ion Concentration
Lactic Acid / blood
Leg / blood supply
Muscle Contraction / physiology*
Muscle, Skeletal / metabolism*
Osmolar Concentration
Potassium / blood,  metabolism*
Regional Blood Flow / physiology
Reg. No./Substance:
0/Catecholamines; 50-21-5/Lactic Acid; 7440-09-7/Potassium

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

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