Document Detail

Effects of dietary magnesium on sodium-potassium pump action in the heart of rats.
MedLine Citation:
PMID:  2826728     Owner:  NLM     Status:  MEDLINE    
Sprague-Dawley rats were fed a basal AIN-76 diet containing 80, 200, 350, 500 or 650 mg of magnesium per kilogram of diet for 6 wk. Ventricular slices, as well as microsomal fractions, were prepared from the hearts and were used to determine sodium-potassium pump activity. Sodium-potassium pump activity was assessed in the microsomal membranes by determining the ouabain-inhibitable Na+, K+-ATPase activity and [3H]ouabain binding, and in the ventricular slices, by determining ouabain-sensitive 86Rb uptake under K+-free conditions. The ATPase activity increased with increasing dietary magnesium, so that in the hearts of those animals that were fed 500 and 650 mg of magnesium/kg diet, it was significantly greater than the activity in the hearts of the animals fed 80 and 200 mg/kg diet. Similarly, 86Rb uptake by heart slices from rats fed 500 and 650 mg of magnesium/kg diet was significantly greater than the uptake by heart slices from animals fed 80 and 200 mg/kg diet. [3H]Ouabain binding did not change with increasing dietary magnesium. Thus, magnesium deficiency appears to have no effect on the number of sodium-potassium pump sites, but does decrease the activity of the pump. It is suggested that this leads to an increase in intracellular Na+, resulting in a change in the membrane potential, and may contribute to the arrhythmias associated with magnesium deficiency.
P W Fischer; A Giroux
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of nutrition     Volume:  117     ISSN:  0022-3166     ISO Abbreviation:  J. Nutr.     Publication Date:  1987 Dec 
Date Detail:
Created Date:  1988-02-17     Completed Date:  1988-02-17     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0404243     Medline TA:  J Nutr     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2091-5     Citation Subset:  IM    
Nutrition Research Division, Health and Welfare Canada, Ottawa, Ontario.
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MeSH Terms
Magnesium / pharmacology*
Microsomes / analysis
Myocardium / metabolism*
Potassium / metabolism*
Rats, Inbred Strains
Rubidium Radioisotopes / diagnostic use
Sodium / metabolism*
Sodium-Potassium-Exchanging ATPase / analysis
Reg. No./Substance:
0/Rubidium Radioisotopes; 7439-95-4/Magnesium; 7440-09-7/Potassium; 7440-23-5/Sodium; EC ATPase

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