The effects of vitamin D deficiency on proteoglycan and hyaluronate constituents of chick bone.

The effect of vitamin D deficiency on proteoglycan and hyaluronate constituents of cortical diaphyseal chick bone was studied. Proteoglycans in rachitic bone showed no significant change with respect to their size, composition, or amount relative to other extractable macromolecular components. In contrast, bone hyaluronate levels were raised in chicks fed on diets that were either vitamin D-deficient or depleted in calcium or phosphate, a 7-fold increase being seen in hypocalcaemic vitamin D-deficient chicks. This increase in hyaluronate was not directly related either to the absence of vitamin D or to abnormal levels of blood calcium or phosphate per se; hyaluronate levels are probably regulated by another factor, not yet identified, that is responsive to changes in vitamin D and mineral metabolism.