Dietary magnesium does not affect blood pressure in spontaneously hypertensive rats.

To determine the therapeutic effectiveness of dietary magnesium in the treatment of established hypertension, 21 male spontaneously hypertensive rats were fed altered levels of magnesium oxide from 17 to 29 weeks of age. The rats were divided into three groups of approximately equal mean baseline systolic blood pressures and fed AIN 76A purified diets containing magnesium at 0.01% (low), 0.05% (normal), and 0.40% (high) levels. Mean systolic blood pressures in the conscious SHR during the 12 week period and terminal direct blood pressures under anesthesia were not significantly different among treatment groups. Total and ultrafilterable serum magnesium concentrations reflected dietary magnesium intake. Total and ultrafilterable serum calcium levels were significantly higher (p less than 0.05) in the low magnesium-fed SHR. Histopathologic alterations indicative of aging did not differ among treatment groups. Therefore, in spite of altered serum mineral status, blood pressure and histopathology were not affected by dietary magnesium.