Xenobiotic Metabolizing Enzyme Response of Rainbow Trout (Oncorhynchus mykiss) to Benzophenone-3 and N,N-diethyl-m-toluamide.

Benzophenone-3 (BP-3) and N,N-diethyl-m-toluamide (DEET) are ingredients of personal care products. Despite the frequent occurrence of both compounds in aquatic environments and the fact that fish are exposed to these chemicals together, their combined effects on xenobiotic metabolizing enzymes and antioxidant enzyme activities have not been studied in aquatic organisms. The aim of this study was to determine the effects of the combination of BP-3 and DEET on cytochrome P450 and antioxidant system in rainbow trout (Oncorhynchus mykiss). For this purpose, juvenile male rainbow trout samples were treated with two different doses (100 and 500 μg/L) of BP-3, DEET, and their combinations for 9 days. Low dose BP-3 + DEET administration increased EROD activity. High-dose BP-3 and high dose BP-3 + DEET administration reduced EROD and PROD activities. Glutathione S-transferase activities of treatment groups were not affected by either individual exposure or co-administration of BP-3 and DEET. Individual administration low dose DEET increased catalase activity, whereas high dose BP-3 increased glutathione reductase activity. The results indicated that cytochrome P450 enzyme activities were affected by the combined administration of BP-3 and DEET. These enzymes are responsible for the metabolism of endogenous molecules and environmental pollutants. Accordingly, exposure to BP-3 and DEET mixture may affect the metabolism of endogenous molecules and other pollutants in fish. Alteration of these enzyme activities highlights the toxicity of BP-3 and DEET for fish and the need to improve strategies for monitoring and removing these contaminants from aquatic environments.