Effect of magnesium deficiency on mineral excretion and concentration in rat serum, heart and kidney

Abstract

Epidemiological evidence suggests that magnesium deficiency may be a factor in the etiology of cardiovascular and renal disease. During moderate magnesium deficiency in rats, caused by feeding 80 mg Mg/kg, however, magnesium levels in the soft tissues were previously shown to vary little. Consequently, in the present study, rats were fed either 80 or 500 mg Mg/kg for 6 weeks, and the concentrations of sodium, potassium, calcium, phosphate and magnesium were determined in serum, heart, kidneys, urine and feces to see whether changes in the levels of these elements, caused by the magnesium deficiency, play a role in the pathogenesis of these diseases. The concentration of oxalate was also determined in the urine. In the heart, both sodium and calcium were increased, while magnesium was decreased slightly in the deficient animals. In the kidney, nephrocalcinosis occurred, along with an increase in sodium and phosphate concentration. The feces contained increased levels of sodium and potassium. The data suggest that magnesium deficiency alters sodium transport. In the case of the heart, this may alter the membrane potential and could account for the cardiac arrhythmias associated with magnesium deficiency.