Effect of low-magnesium diet on the histology and the activity of certain enzymes of rat myocardium.

Rats kept on a low-magnesium diet for 14 weeks developed increasing clinical symptoms, from slight trophic changes to inhibition of growth. Focal fragmentation of myocardial fibers was followed by focal fuchsinophilia and later--by focal necrosis. Increasing morphological lesions were associated with calcium salts deposition in the degenerated myocardial fibers, connective tissue and wall of cardiac blood vessels. The low-magnesium diet did not affect the activity of ATP-ases and cytochrome oxidase. The areas of myocardial degeneration and necrosis were free of the activity of alkaline phosphatase and succinic dehydrogenase.