Estimation of metallothionein synthesis in cadmium-exposed human lymphocytes by gel electrophoresis and silver staining.

Metallothionein (MT) is a low molecular weight metal-binding protein that is induced by a variety of heavy metals, and therefore is a candidate for an index in the biological monitoring of heavy metal exposure. As an approach to the establishment of a practical monitoring method, we estimated the MT levels in Cd-exposed cultures of human peripheral blood mononuclear cells as well as purified lymphocytes using a technique developed for the electrophoretic analysis of MTs. By this procedure, we could successfully detect the MTs induced by Cd in a dose-dependent manner. MTs were detectable even in cells exposed to as low as 0.5 microM Cd, which is close to the blood Cd levels of exposed workers. These results indicate the usefulness of this technique as a practical method for the monitoring of heavy metal exposure.