PREVENTIVE EFFECTS OF PRETREATMENT WITH CADMIUM ON ACUTE CADMIUM POISONING IN RATS

It was previously reported that mice pretreated with small doses of cadmium developed a tolerance to a subsequent acute cadmium poisoning. The present experi- ment intended to explain this tolerance mechanism by an animal experiment.Male rats were used as experimental animals, of which one group was adminis- tered intraperitoneally 0.6 mg cadmium per kg of body weight as pretreatment and 24 hr later 3 mg cadmium per kg of body weight was injected intraperitoneally as challenging. Another group was injected with 3 mg cadmium per kg intraperitoneally. About all rats, the determination of cadmium was made in each organ, urine, and feces for 7 days after challenging.In the pretreatment group, it was recognized that the cadmium contents in liver increased remarkably compared with nonpretreatment group, on the contrary, the cadmium content in blood, especially in serum, and in other organs, and the amount of cadmium excreted in urine decreased in pretreatment group compared with non-pretreatment group.