Plasma 65Zn kinetics in the rat.

The amount of 65Zn in the plasma of rats after intravenous injection was found to decline following closely two-compartment kinetics over a period of 90 min. Comparative analysis of the amount of 65Zn present in the two kinetic pools at various time-intervals post-injection with the actual physiological location of the 65Zn, revealed that the initial pool (Qa) is primarily the blood plasma, while the second pool (Qb) is primarily within the liver. The plasma Zn concentration and Qa were both found to fall reproducibly during Zn depletion, whereas Qa and Qb increased following injection of Escherichia coli endotoxin in contrast to the decline in plasma Zn concentration. Further investigation of the nature of Qb indicates that it represents in part a metabolic pool within the liver which varies substantially in response to Zn status in a manner similar to metallothionein.