Effects of dietary magnesium on sodium-potassium pump action in the heart of rats

Journal Article · Tue Dec 01 04:00:00 EST 1987 · J. Nutr.; (United States)

OSTI ID:5550936

Fischer, P W; Giroux, A

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 (/sup 3/H)ouabain binding, and in the ventricular slices, by determining ouabain-sensitive /sup 86/Rb 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, /sup 86/Rb 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. (/sup 3/H)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.

• Research Organization: Health and Welfare Canada, Ottawa, Ontario
• OSTI ID: 5550936
• Journal Information: J. Nutr.; (United States), Journal Name: J. Nutr.; (United States) Vol. 117:12; ISSN JONUA
• Country of Publication: United States
• Language: English

Related Subjects

550501 -- Metabolism-- Tracer Techniques
560300* -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACID ANHYDRASES
ALKALI METAL ISOTOPES
ALKALI METALS
ALKALINE EARTH METALS
ANIMALS
ATP-ASE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BODY
CARBOHYDRATES
CARDIAC GLYCOSIDES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
CELL MEMBRANES
DAYS LIVING RADIOISOTOPES
DIET
DRUGS
ELEMENTS
ENZYME ACTIVITY
ENZYMES
GLYCOSIDES
HEART
HYDROLASES
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
MAGNESIUM
MAMMALS
MEMBRANE TRANSPORT
MEMBRANES
METALS
MICROSOMES
MINUTES LIVING RADIOISOTOPES
MUSCLES
MYOCARDIUM
NUCLEI
NUTRITIONAL DEFICIENCY
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
OUABAIN
PHOSPHOHYDROLASES
POTASSIUM
RADIOISOTOPES
RATS
RODENTS
RUBIDIUM 86
RUBIDIUM ISOTOPES
SODIUM
STROPHANTHINS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES