Changes in leucocyte cytochrome oxidase activity associated with deficiency of copper in laboratory and farm animals

The cytochrome oxidase activity of circulating leucocytes was investigated by means of a semiquantitative method using blood films. A significant decrease in activity was found in male rats, cattle and sheep that had been deprived of copper. During copper depletion, leucocyte cytochrome oxidase activity declined more slowly than did plasma copper concentration and plasma ferroxidase I activity, and so was less sensitive as a guide to the copper status of the animal.