Metallothionein induced by cadmium or zinc inhibits lipid peroxidation in rats exposed to dimethylnitrosamine.

Dimethylnitrosamine (N-nitrosodimethyamine) is a potent inducer of microsomal lipid peroxidation in the liver and kidneys. The results of this study show that prior exposure of adult rats to cadmium or zinc antagonises the effect of dimethylnitrosamine on lipid peroxidation by inducing increased metallothionein synthesis. Increased concentration of reduced glutathione (GSH) in the liver and kidney of rats pre-treated with cadmium or zinc and exposed to dimethylnitrosamine suggests that metallothionein inhibits oxidative stress. The presented results have been corroborated by findings that exposure of adult rats to cadmium or zinc may activate genes for metallothionein and glutathione-S-transferase, the protective proteins against oxidative stress.