Metallothionein gene expression in peripheral lymphocytes from cadmium-exposed workers

Metallothionein (MT) plays an important role in the detoxification of cadmi um. investigate the usefulness of MT gene expression in peripheral blood ly mphocytes (PBLs) as a biomarker of cadmium exposure and susceptibility, rev erse transcriptase-polymerase chain reaction was used to measure the MT gen e expression in PBLs from cadmium-xposed workers. Both basal and induced MT expressions were found to increase with increased blood cadmium (BCd) and urinary cadmium (UCd) levels. Both basal and induced MT expression levels w ere significantly correlated with the logarithm of BCd and the logarithm of UCd levels. The dose-response relationship between internal dose of cadmiu m and MT expression suggested the validity of MT expression in PBLs as a bi omarker of cadmium exposure. In vitro induced MT expression level in PBLs w as found to be inversely related to the level of renal dysfunction indicato r, urinary N-acetyl-beta -D-glucosaminidase (UNAG). The latter finding indi cates that MT expression in PBLs may be a useful biomarker of susceptibilit y to renal toxicity of cadmium. (Presented in part at the International Sym posium on Metal-Binding Proteins in Biology, Banff, Canada, 1998.)