Influence of dietary magnesium on cardiac and renal lesions of young rats fed an atherogenic diet.

Young male rats fed an atherogenic diet for 24 to 26 days developed magnesium deficiency. The renal lesions, calcium deposition in tubular lumens in the outer zona intermedia, are morphologically consistent with those seen in animals fed magnesium-free diets. It was necessary to feed 8 to 16 times the normal requirement of magnesium to prevent completely these lesions. The limitations in the pathogenesis of these renal lesions are discussed. The addition of 2 mg. per cent of thyroxine to the diet markedly lowered or abolished deposition of calcium in the kidney; it also lowered atherogenesis to a minimum but did not abolish it. Early lesions of atherosclerosis of the cardiac valves and of the aorta were observed. These were more prominent in animals on a 10 per cent than in those on a 20 per cent protein diet. The atherosclerosis was diminished but not abolished by exceedingly high dietary levels of magnesium in the 10 per cent protein group. Such a decrease was not noted in the 20 per cent protein group. There did not appear to be significant variation in the morphology of the fatty livers in and between the various groups and subgroups as judged by staining with Sudan IV.