FATE OF CADMIUM BOUND TO PHYTOCHELATIN IN RATS

The fate of cadmium(Cd) bound to phytochelatin [PC, (gamma-Glu-Cys)n-G ly)] was studied in rats using synthesized Cd-109-PC. Less Cd was abso rbed through the digestive tracts than CdCl2, but the ratio of renal C d to hepatic Cd was higher. After parenteral administration of Cd-PC, Cd was distributed mainly in the liver, Kidney, small intestine and pa ncreas. More Cd was found in the kidney than the liver after Cd-PC (n= 5) administration. Most of the Cd was bound to the high molecular weig ht fraction in the hepatic cytosol 0.5 hr after administration and mov ed to the metallothionein fraction at 6 hr. The tissue distribution of Cd was not affected even when free PC (n=5) was administered 3 hr aft er or before Cd injection. The distribution in the kidney increased on ly in the case of the simultaneous administration of Cd with PC. These findings show that the absorbance of Cd bound to PC from the alimenta ry tract is lower than that of CdCl2 although absorbed Cd is distribut ed to the kidney more than CdCl2, and Cd is liberated from PC soon aft er uptake by the cells.