Popis: |
The purpose of this investigation was to examine the nature of the protective role of glutathione (GSH) in liver and gills of channel catfish (Ictalurus punctatus) exposed to chlorothalonil (2,4,5,6 tetrachloroiso-phthalonitrile). In an initial experiment, the acute toxicity of chlorothalonil was enhanced three-fold after channel catfish were depleted of liver and gill GSH by l -buthionine S.R-sulfoximine (BSO. 1000 mg/kg i.p.) and diethyl maleate (DEM, 0.6 ml/kg i.p.), indicating that GSH plays a critical role in mitigating acute chlorothalonil toxicity in this species. In a subsequent experiment, sublethal exposure to chlorothalonil elicited significant increases (p 0.05). These results indicate that the mechanism of GSH induction in liver and gills of catfish exposed to chlorothalonil involves increased cysteine uptake and also increased GCS activity. The results of this study support the hypothesis that simultaneous exposure to multiple environmental chemicals that utilize or deplete tissue GSH may predis pose fish to acute toxicity. |