Levels of cellular glutathione and metallothionein affect the toxicity of oxidative stressors in an established carp cell line

The comparative toxicity of a variety of oxidative stressors was studied in the epithelioma papulosum cyprini line from carp using the neutral red cyt oxicity assay. LC50's decreased in the order t-butylhydroperoxide > hydroge n peroxide > diquat > paraquat. The cytoxicity of hydrogen peroxide was sig nificantly reduced when the cells were grown in L-15 medium rather than MEM and this could be attributed to elevated cellular glutathione and metallot hionein levels and higher activities of GSH-dependent detoxification system s. The protective effect of metallothionein in radical scavenging was demon strated by decreased toxicity of the redoxcycling toxicants, diquat and men adione after metallothionein levels had been pre-induced by Cd-exposure. Th is study demonstrates the relationship between toxic effects of oxidative s tressors and expression of detoxification systems in fish. (C) 2000 Elsevie r Science Ltd. All rights reserved.