Effect of Cysteine on the Fate of Cadmium in Rats-LD50 and Transition of Cadmium-

The LD50 of cadmium chloride to rats was studied after oral administration with or without L-cysteine, and the accumulation and excretion of cadmium were also examined during continuous oral administration.The LD50 of cadmium chloride by single oral administration to rats was 204.2mg/kg. However, in the presence of L-cysteine (1500mg/kg), the LD50 decreased to 58.3mg/kg.Compared with the rats given continuous oral administration of cadmium chloride (10mg/kg/day) alone for 8 weeks, the simultaneous oral dosing of cadmium chloride (10mg/kg/day) and L-cysteine (1500mg/kg/day) increased the amount of cadmium retained in the organs. Cadmium retained in the organs reached a maximum level after 6 weeks. In the rats given cadmium chloride, the urinary excretion of cadmium was about 0.1μg/day through 8 weeks. In the rats given L-cysteine with cadmium chloride, the daily excretion of cadmium was similar (0.1μg) until cadmium retained in the organs reached the maximum level. Thereafter, the urinary excretion of cadmium increased markedly to about 1.0μg/day.