TISSUE DISTRIBUTION STUDIES OF IONIC AND CHELATED ZN⁶⁵ IN MICE

¹ Montefiore Hospital, New York, and Veterans Administration Hospital, Hines, Illinois

The excretion and tissue distribution of intravenously administered tracer amounts of Zn⁶⁵Cl₂, Zn⁶⁵EDTA, and Zn⁶⁵DTPA were studied in mice. The excretion of ionic zinc is relatively low. The main pathway of excretion is via the intestine. The excretion of chelated zinc is high and rapid and the main pathway is via the kidney. Zinc⁶⁵ leaves the vascular system rapidly with equilibration occurring 4 hours after injection as the Zn65Cl2 and at 1 hour after injection of Zn⁶⁵DTPA or Zn⁶⁵EDTA. The concentration of Zn⁶⁵ in ionic and chelated form is highest in the pancreas, liver, and intestine. The uptake of ionic zinc was higher than that of chelated zinc in each organ and the uptake of Zn⁶⁵DTPA was higher than Zn⁶⁵EDTA. The data indicate that redistribution of ionic and chelated zinc differs with time in certain organs.