Oxidation, excretion, and tissue distribution of [26-14C] cholesterol in copper-deficient rats

The effect of copper deficiency on in vivo catabolism and excretion of [26-14C] cholesterol was studied in male rats. The study involved four treatments, namely, control, copper-deficient, control plus cholesterol, and copper-deficient plus cholesterol supplement. Significant elevations of serum ester and total cholesterol concentrations and reductions of serum free, ester, and total cholesterol specific activities were observed in rats fed the copper-deficient diets. In addition, a significant reduction of liver free cholesterol concentration was observed in rats fed the copper-deficient diets. Cholesterol supplementation significantly increased the concentrations of, and reduced the specific activities of, the different serum and liver cholesterol fractions. The only exception was that the liver free cholesterol concentration was not altered by cholesterol supplementation. The serum free cholesterol concentration was significantly increased and the specific activities of liver ester cholesterol were significantly reduced in rats fed the copper-deficient diet with no added cholesterol. The rates of oxidation and excretion of [26-14C] cholesterol were not influenced by dietary copper but were significantly increased by cholesterol supplementation. A shift of cholesterol from the liver to the serum pool appeared to be responsible for the hypercholesterolemia observed in copper deficiency.