Vitamin D, Calcium, and Protein Synthesis

Abstract

This chapter discusses the vitamin D transformations, calcium transport, and protein synthesis. The vitamin D affects the formation of specific proteins that appear to be concerned with calcium metabolism. In intestine, calcium-binding protein is identified in several species and the synthesis of this protein is absolutely dependent on the presence of vitamin D. The majority of the evidence indicates CaBP to arise by de novo synthesis and by the action of a specific messenger RNA, at least in the chick. The proteins that increase as a consequence of vitamin D are the phosphatases—alkaline phosphatase, CaATPase, and phytase—and each of these may represent different manifestations of the same macro-molecular complex. In the kidney, the effect of vitamin D shown on this organ is the induction of CaBP synthesis. In bone, vitamin D repletion has important effects on collagen synthesis and metabolism, particularly on the cross-linking reaction and hydroxylation of lysyl residues. The chapter also discusses the general effects of vitamin D and calcium on cell, metabolism, and growth.