Effect of vitamin D on plasma citrate and calcium response to nephrectomy

¹ Ladd Chemical Laboratories, North Dakota Agricultural College, Fargo, North Dakota; and Department of Biochemistry, The Medical School, Northwestern University, Chicago, Illinois

Young rats fed a diet deficient in vitamin D and optimal in calcium and phosphate respond to prophylactic administration of the vitamin with elevated plasma citrate and calcium levels. Feeding vitamin D to D-deficient young rats markedly increased the plasma citrate response to nephrectomy. The D-deficient animal requires between 24 and 48 hr to develop the maximal response to vitamin D as judged by the plasma citrate response to nephrectomy. The plasma citrate response to nephrectomy after administration of the vitamin is virtually linear over a narrow range of vitamin D dosage. These data are discussed in terms of the possible role of citrate in relation to parathyroid function and the maintenance of plasma concentration of calcium.