Intestinal Calcium-Binding Protein and Rickets 1

Abstract

Summary

To determine the influence of dietary phosphate deficiency and rickets on the level of intestinal calcium-binding protein, weanling rats were raised on 2 types of vitamin D-deficient diets. A group fed a rachitogenic diet, which was vitamin D-free, high in calcium, and low in phosphorus, developed rickets as measured by increased lactate formation after in vitro incubation of tibial epiphyseal cartilage slices. A second group, fed the same diet supplemented with phosphate, did not develop rickets. The level of intestinal calcium-binding activity was the same in animals raised on both dietary regimens and vitamin D administration induced an increase in binding activity of the same magnitude in both groups of rats. Thus the synthesis of calcium-binding protein appears to be independent of dietary phosphate deficiency and of the presence of rickets.