6~ZINC DISTRIBUTION IN VARIOUS TISSUES OF ZINC- DEFICIENT AND NORMAL BULL CALVES WITH TIME AFTER SINGLE INTRAVENOUS OR ORAL DOSING 1, 2

In two experiments, 65Zn distribution was studied in several tissues of zinc-deficient and normal bull calves over periods of 56-70 days following single oral or intravenous dosing. With some tissues, such as liver, 65Zn level reached a peak within a very few days after either method of dosing. In others, including red blood cells, muscle, bone, and hair, a peak did not occur until several weeks after oral or intravenous dosing. In both orally and intravenously dosed animals, skin, testicle, scrotum, kidney, muscle, heart, lung and spleen, from zinc-deficient, animals contained a higher percentage of the total body burden than did comparable tissues of normal animals. Pancreas from controls contained more 65Zn. In all instances, bones of control animals contained much higher levels of 65Zn than those from deficient ones. Rib and tuber coxae bones contained higher 65Zn levels than did tibia.