Bone composition and phosphatase activity in magnesium deficiency in rats.

The effect of magnesium deficiency on phosphatase activity and bone composition was determined in the femora of young rats. In the right distal metaphysis the acid and alkaline phosphatase activities were decreased in magnesium-deficient rats, and the activity of bone alkaline phosphatase in the incubation mixture after adding magnesium was significantly greater in the magnesium-deficient than in the control rats. In the left distal metaphysis the water content was significantly lower in the magnesium-deficient rats at the fifth week but not at the third week. Conversely, the ash content of metaphyseal bone was significantly increased in magnesium-deficient rats at the fifth week, but not at the third week. The magnesium and phosphorus contents were abnormally low in the deficient bone at both periods. The calcium content was increased in the deficient bone at the third week, but not at the fifth week.