Specificity of zinc pathway through the body: turnover of Zn65 in the mouse

An isotopic study is presented which shows that zinc metabolism is controlled by at least two homeostatic mechanisms which act at the sites of absorption and of intestinal excretion, respectively. Zinc was the only element which, when used as a metabolic load, accelerated the elimination of Zn65. Among its neighbors in the transition series, copper and gallium were ineffectual. Among the members of group II of the elements cadmium decelerated the excretion of Zn65 slightly, whereas magnesium was without demonstrable effect. The significance of these findings relative to the specificity of zinc's pathway through the body is discussed.