The toxicology and metabolism of chlorothalonil in fish. IV. Zinc coexposure and the significance of metallothionein in detoxication in Salmo gairdneri

Abstract

Rainbow trout, Salmo gairdneri, were subjected to various regimes of exposure to zinc (0.36 mg/l) and 14C-chlorothalonil ( 14C-TCIN, 10 μg/l). Gel column chromatography of hepatic cytosol after exposure showed no binding of 14C-TCIN to metallothionein proteins with or without pre-exposure or with coexposure to zinc. 14C-TCIN did not induce the production of metallothionein with or without 96 h preexposure to 0.36 mg/l zinc, whereas induction did occur with zinc coexposure over 156 h. 14C-TCIN exposure did not affect cytosolic zinc levels, but exposure to zinc did reduce the level of cytosolic 14C-TCIN over the observed protein molecular weight range. It appears that metallothionein does not play a significant role in TCIN detoxication at this sublethal exposure level.