Calcium Metabolism in Manganese-Deficient and Zinc-Deficient Rats

SummaryThe metabolism of calcium was studied in manganese-deficient and zinc-deficient rats by a method combining a kinetic study using 45Ca with a short-term classical balance study. There were no differences in managanese-deficient rats as compared with controls in any of the parameters of calcium metabolism, including pool size, endogenous fecal calcium, urinary clacium, or in the rates of calcium entering or leaving bone. The zinc-deficient animals, however, showed significant decreases, as compared with both ad libitum and restricted-intake controls, in a number of parameters of calcium metabolism. These included the rates of calcium entering and leaving bone, pool size, the rate of slow exhange, and the slowly exchangeable calcium in bone. The results suggest that the skeletal abnormals are not the result of abnormal calcium metabolism. In zinc deficiency, on the other hand, specific effects on calcium metabolism were noted. Thus it appears that zinc, but not manganese, is required for normal metabolism of calcium.