Influence of zinc and calcium deficiency on the concentrations of calcitonin, parathyroid hormone, and 25-hydroxy-vitamin D3 in rat serum.

48 male Sprague-Dawley rats with an average live weight of 141 g were assigned to four groups of 12 animals each. Group I was fed the basal diet (63 mg/kg of Zn, 8.8 g/kg of Ca), group II received a Ca-deficient diet (0.043 g/kg of Ca), group III was fed a Zn-deficient diet (1.1 mg/kg of Zn), and group IV received a diet with a combined Zn- and Ca-deficiency (1.1 mg/kg of Zn; 0.043 g/kg of Ca). Each of the four groups was fed the same daily quantity of rations, which was based on the food uptake of the deficient groups III and IV. After 28 days of the experiment, the rats were anesthesized with ether and sacrificed. In the obtained serum, the concentrations of calcitonin, parathyroid hormone, and 25-hydroxy-vitamin D3 were measured by radioimmune assays. The Zn- and Ca-concentrations in the serum served as parameters for the status of Zn- and Ca-supply. 1. Dietary Ca-deficiency had no influence on the development of live weight of the rats in the case of restricted feeding. Zn-deficiency, however, strongly reduced live weight development. 2. Alimentary Ca-deficiency reduced the Ca-concentration of the serum by 34%, the calcitonin concentration by 17%, and the 25-hydroxy-vitamin D3 concentration by 82% as compared to the levels in control animals, whereas the concentrations of Zn and parathyroid hormone remained unchanged. 3. Alimentary Zn-deficiency reduced the Zn-concentration of the serum by 63% as compared to the control animals, whereas the concentrations of 25-hydroxy-vitamin D3 and parathyroid hormone were increased.(ABSTRACT TRUNCATED AT 250 WORDS)