Tissue accumulation of cadmium as a function of blood concentration

We have provided data relating Cd concentration in tissue to about a 40-fold range in blood Cd concentration. Osmotic pumps containing cadmium chloride were subcutaneously implanted in male New Zealand white rabbits. The pumps continuously delivered either 0.15 or 1.5 mg Cd/d. Blood and plasma levels of Cd were measured weekly throughout the study. After 28 d, the rabbits were killed and tissue concentrations of Cd determined by atomic absorption spectrophotometry. Less than 10% of the total Cd in the blood was carried in the plasma, the remainder was associated with the blood cells, where it was bound mainly to metallothionein. We found the blood and tissue levels of Cd were correlated for each tissue we investigated. There was a wide range in affinity of the tissues for Cd; liver and kidney had the highest Cd uptake, whereas brain affinity was about 500 times less than liver.