Effect of pretreatment with cadmium/cysteine or metallothionein on accumulation of cadmium challenged with either complexes.

The effect of pretreatment with cadmium (Cd) complexes on the distribution and accumulation of Cd in the liver and kidneys was examined for the Cd complexes that are reabsorbed site-selectively at the renal proximal tubules of rats. Cd was administered simultaneously with excess cysteine or as metallothionein (MT) and then challenged by either complex, the former complex being reabsorbed preferentially at the S3 segment of proximal tubules of the outer stripe of the outer medullary zone, while the latter complex was reabsorbed at the S1 + S2 segments of proximal tubules. Cd in the kidneys was increased by pretreatment with either complex. On the other hand, pretreatment reduced the distribution of Cd to the liver. However, no site-selective effects were observed with either complexes. Calcium concentration, which was elevated significantly in the kidneys by a single injection of both complexes, was reduced by pretreatment.