Objective  To observe the activities of hepatic CYP450 and CYP1A1 enzymes in the liver of Carassius auratus statically exposed to water polluted with isocarbophos and to assess the biological effects of isocarbophos on water body.

Method  All Carassius auratus samples were divided into four experiment groups (concentration of isocarbophos:5.0, 10.0, 15.0, and 20.0 mg/L) and one control group. The four experiment groups were then statically exposed to designed isocarbophos polluted water. After 24, 48, 72, and 96 h, the activities of CYP450 and CYP1A1 enzymes in liver microsome of Carassius auratus were measured. Meanwhile, the concentrations of isocarbophos in water samples were detected by gas chromatography, and the correlation between the concentrations of isocarbophos and the activities of CYP450 and CYP1A1 were evaluated.

Result  Within 24 h of exposure, compared with the control group, the liver total CYP450 enzyme activity in experiment group did not change, but the CYP1A1 enzyme activity in the 20.0 mg/L experiment group was higher than that in the control group (P<0.05). After 48 h of exposure, compared with the control group, the activities of total CYP450 and CYP1A1 enzymes in all experiment groups were obviously increased (P<0.01). After 96 h of exposure, the total CYP450 enzyme activity and the CYP1A1 enzyme activity of the 20.0 mg/L experiment group were 1.29 times and 1.54 times respectively higher than the corresponding indices of the control group. After 24 h of exposure, there were no correlations between the residues of isocarbophos and the activities of total CYP450 and CYP1A1 enzymes (P>0.05), but after 48 h of exposure, there existed positive correlations and the correlation coefficients were all over 0.9 (Ps<0.05).

Conclusion  Isocarbophos exposure could cause increased activities of CYP450 and CYP1A1 enzymes in Carassius auratus livers. After 48 h of exposure, isocarbophos concentrations in water and the activities of CYP450 and CYP1A1 enzymes are positively correlated.