The effects of parathyroidectomy on the development of nephrocalcinosis in rats fed phosphate-supplemented and unsupplemented diets containing alpha protein.

The effects of parathyroidectomy (PTX) on the development of nephrocalcinosis in rats fed a diet containing alpha protein were investigated for the purpose of determining whether the nephrocalcinosis was phosphate-induced. PTX completely prevented the occurrence of nephrocalcinosis in rats fed a phosphate-supplemented commercial laboratory diet for 4 weeks. However, PTX did not completely prevent the occurrence of nephrocalcinosis in rats fed a phosphate-supplemented alpha protein diet. Several calciferous deposits were found in the inner medulla. The same was also found in rats that underwent sham operations and PTX rats fed the basal alpha protein diet. Total renal calcium and phosphorous levels in these three groups were also similar and were about twice as great as those in corresponding groups fed phosphate-supplemented and unsupplemented commercial laboratory diets. Therefore, we conclude that the nephrocalcinosis in rats fed a basal alpha protein diet is not induced by PTH or excess phosphate, but is induced by some other factor associated with the diet.