Effects of 2,4-dichlorophenoxyacetic acid and picloram on biotransformation, peroxisomal and serum enzyme activities in channel catfish (Ictalurus punctatus).

Channel catfish (Ictalurus punctatus) exposed to a mixture of picloram and 2,4-dichlorophenoxyacetic acid (2,4-D) for 10 days displayed increased activities of hepatic ethoxyresorufin O-deethylase (EROD), decreased serum chloride concentrations and decreased liver/body weight ratios. These changes were not observed in fish exposed to either compound alone. Neither compound, nor their mixture, increased hepatic peroxisomal catalase or lauroyl CoA oxidase activities. The results of this study indicate that 10-day exposure of 2,4-D or picloram does not induce peroxisomal enzymes in channel catfish; however, exposure to a mixture of 2,4-D and picloram may cause physiological effects to catfish not observed with either compound alone.