摘要：The uptake of labeled cadmium by isolated human erythrocytes was studied. The uptake of cadmium, usually studied at 37°, was determined by the increase of the radioactivity of 109Cd in the erythrocytes. Cadmium was taken up slowly, and the amount was dependent on cadmium concentration in the medium in the range of 1.2 to 36.6 ppm. Starvation of erythrocytes, incubated at 37°, unaffected cadmium uptake, and cadmium uptake was not observed at 0°. The uptake of cadmium by ATP-loaded cells was lower than that by ATP-unloaded cells. The uptake of cadmium by erythrocytes does not seem to be closely coupled to energy production. Fifteen amino acids were tested for their capacity to influence the uptake of cadmium. Cysteine was powerfully inhibitory. Histidine stimulated the uptake of cadmium at levels of 5 and 10 ppm cadmium, but inhibited it at a level of 50 ppm cadmium. Histidine also enhanced the binding of cadmium to stroma at 10 ppm cadmium. Stimulation of cadmium uptake was recognized in imidazole but not in 1-methylimidazole. It was suggested that stimulation of cadmium uptake was possibly due to the enhanced transport of cadmium across the erythrocyte membrane in the form of cadmiumhistidine complex.
