Increases of serum phosphorus concentration and duodenal, renal and femur alkaline phosphatase (EC 3.1.3.1) activities of normal rats fed 2000 ppm aluminum diets.

In order to investigate the dietary effect of calcium on aluminum-induced hypophosphatemia, five types of diet, sucrose, lactose, milk, casein and soy protein, were prepared. These diets differed with regard to Ca concentration, and carbohydrate or protein sources which were expected to modify intestinal Ca absorption. Weanling Wistar rats were fed these diets for 67 days with the addition of Al at a concentration of 2000 ppm. Nutritional constituents had little effect on Al accumulation in the duodenum and bone. Al treatments had no effects on increases of body weight. The Al treatments significantly increased duodenum alkaline phosphatase (ALPase) activity and serum phosphorus concentration in all of the dietary groups. Slight but significant decreases of bone weight were observed. There were no significant increases in serum Al concentration but bone and kidney ALPase activities were also observed. These results suggest that Al ingestion can cause hyperphosphatemia in the intact animal. Effects of Al on nutrition should be considered even if serum Al concentration does not increase.