Effects of Severe Phosphate Deprivation in Growing Chicks and Possible Role of Vitamin D

Abstract

When growing rats are restricted to a diet very low in phosphate, they develop hypophosphatemia, hypercalcemia, hypercalciuria and almost complete suppression of phosphate excretion in the urine and there is progressive loss of calcium and phosphate from the skeleton^1,2,3. There would appear to be potent homeostatic mechanisms to ensure a supply of phosphate for the growing soft tissues. Since hypophosphatemia stimulates the synthesis of the active metabolite of vitamin D₃, 1,25 dihydroxycholecalciferol,⁴ the question arises as to whether vitamin D is essential for the homeostatic changes associated with severe phosphate deprivation. The following studies were carried out on young chicks, which are particularly sensitive to the effects of vitamin D.