The current research aims to determine alterations in gene expression and enzymatic activity of fish antioxidant metabolism in response to pesticide administration. To this end, three different deltamethrin concentrations (0.25, 1, 2.5mug/L) were administrated to rainbow trout (Oncorhynchus mykiss) at different time intervals (6, 12, 24, 48 and 72h) in order to observe the influences of the pesticide on the activity of glutathione reductase, glucose 6-phosphate dehydrogenase, 6-ghosphogluconate dehydrogenase, and the expression of Hsp70 gene. We observed that the activities of the enzymes decreased with increasing deltamethrin concentrations and exposure time. The pesticide had more inhibitory effects on gill enzymes than those of muscle, liver and kidney. In addition, we detected that deltamethrin increased the expression of the stress-related protein Hsp70 with significant fold-chance values. The efficiency rate was 96.4% which is equal to 1.96 calculated via conversion formula used to calculate fold-chance value. We conclude that deltamethrin causes oxidative stress in fish both at protein and mRNA levels.
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