EFFECT OF PRIOR, LOW-LEVEL CADMIUM EXPOSURE IN-VIVO ON METALLOTHIONEIN EXPRESSION IN CULTURED LYMPHOCYTES

Exposure to cadmium (Cd) is currently monitored by measurement of the metal in blood or urine, or by observation of excreted compounds such as beta(2)-microglobulin or N-acetyl-beta-D-glucose. Whilst these appr oaches are useful for the detection of acute exposure to Cd, their app licability in the management of long-term, low-level exposure is less clear. Metallothioneins are ubiquitous proteins that are synthesized i n response to heavy metal ions and may offer themselves as being a bio logically sensitive indicator of Cd exposure. We have examined both ba sal and Cd-induced metallothionein mRNA levels in cultured lymphocytes from groups with different exposures to Cd, attempting to assess thei r potential as an indicator of Cd exposure and the suitability of such an assay for routine analysis. We found that induced metallothionein mRNA levels, father than basal mRNA levels, increased in groups known to have received elevated body burdens of Cd, although these increases were not significant between groups. There was, however, a significan t correlation between induced metallothionein mRNA levels and urinary beta(2)-microglobulin. These results suggest that further work on the in vitro lymphocyte response to Cd as a diagnostic tool is warranted.