Effects of glutathione depletion on copper cytotoxicity in oysters (Crassostrea virginica)

Glutathione is a tripeptide that plays an important role in ameliorating me tal toxicity. Depletion of glutathione has been associated with an increase d risk of metal toxicity in mammals. An understanding of the toxicological significance of glutathione depletion in oysters would be of considerable i mportance given the widespread use of bivalves in biological monitoring. La boratory studies were conducted by using an inhibitor of glutathione synthe sis (buthionine sulfoximine) to investigate the effects of glutathione depl etion on metallothionein expression, lysosomal membrane destabilization, an d lipid peroxidation in Cu-exposed oysters. In oysters exposed to Cu (20 an d 80 mu g/l) and buthionine sulfoximine (20 mg/l), metallothionein inductio n was suppressed and cellular stress responses were frequently higher than those observed in oysters exposed singly to Cu. Together, these results sug gest that environmental conditions that cause glutathione depletion may inc rease the potential for adverse effects to pollutants during in situ exposu res. (C) 2000 Elsevier Science B.V. All rights reserved.