Induction of intestinal brush border alkaline phosphatase by vitamin D and identity with Ca-ATPase

VITAMIN D may increase the rate of intestinal transport of calcium through a primary action on nucleic acid and protein synthesis^1,2. Wasserman and Taylor have detected a calcium binding protein in chick intestine which is induced by vitamin D³. Harmeyer and DeLuca, however, reported a discrepancy between the time course of change in calcium transport and of the increase in calcium binding protein⁴. In addition, calcium binding protein appears in the soluble portion of the cell³, whereas the major site of vitamin D action may be at the level of microvillar membrane ^5,6. Thus, a comparison of isolated intestinal microvilli from vitamin D deficient and repleted animals might reveal other specific alterations which could be related to the action of vitamin D.