Accumulation and Toxicity of Orally Ingested Cadmium in Metallothionein Null Mice

Abstract

To investigate the role of metallothionein (MT) on the accumulation and toxicity of orally administered cadmium (Cd), metallothionein null and 129/Sv mice were fed a Cd-containing diet (50ppm) for four months. Cd concentrations in the liver and kidney of MT null mice did not exceed 10μg/g throughout the exposure period, while a time-dependent increase in tissue Cd concentrations was observed in the control mice. However, no apparent nephrotoxicity was observed in MT null mice, as is contrary to previous observations in which repeated subcutaneous injections of Cd caused renal dysfunction in MT null mice, though the renal Cd concentrations did not exceed 10μg/g. The results of this study suggest that the route of Cd administration plays an important role in the manifestation of Cd nephrotoxicity, even in the absence of MT.