Influence of cholecalciferol on tissue zinc homeostasis in the rat

A role for calciferol in zinc homeostasis was investigated by radioisotope uptake and compartmental analysis techniques. Cholecalciferol was injected into rats 4-5 days prior to radioisotopic study of rapidly exchangeable pools (<4 h). Kidney, liver, and duodenum had significant increases in zinc uptake rates. Bone and skeletal muscle had significant decreases. No other tissues had significant differences. Compartmental analysis models generated by the SAAM-25 digital computer program suggested a decrease in the fractional tissue to plasma coefficient to be the mechanism for the observed changes in the serum zinc concentration and tissue zinc accumulation rates. It is not clear whether this is a specific effect of calciferol on zinc homeostasis or is a nonspecific response which may reflect some role for zinc in calciferol metabolism.