GLUTATHIONE CONCENTRATIONS IN THE HARD CLAM, MERCENARIA-MERCENARIA, FOLLOWING LABORATORY EXPOSURE TO LEAD (A POTENTIAL MODEL SYSTEM FOR EVALUATING EXPOSURE TO CARCINOGENS AND TOXINS)

This study determined whether M. mercenaria retain Pb from sea water and whether endogenous GSH acts as an important primary response modulator of heavy metal detoxification. Lead accumulation in M. mercenaria may be related to the rate of endogenous formation of GSH. Glutathione concentrations decrease with increasing early exposure to Pb and increase after continued acute exposure. M. mercenaria do not accumulate Pb but appear to reach an equilibrium with their environment. GSH formation may protect the hard clam from accumulating excess Pb by forming insoluble sulfide adducts with Pb and excreting these complexes.