Detoxifying Enzymes in Adults and Nymphs of the German Cockroach: Evidence for Different Microsomal Monooxygenase Systems

Detoxification enzyme assays were conducted on last-instar nymphs and adult males of the Village Green strain of German cockroach. Activities of glutathione transferases, general esterase, carboxyesterases, and reductases were the same in nymphs and adult males. However, microsomal enzyme assays revealed that aldrin epoxidase, phorate sulfoxidase, methoxyresorufin O-demethylase, and biphenyl hydroxylase activities were significantly higher (4- to 15-fold) in the adult male, whereas aniline hydroxylase, ethoxycoumarin O-deethylase, p-chloro-N-methylaniline N-demethylase activities and total cytochrome P450 content were not different. Equivalent cytochrome P450 content and disparate enzyme activity toward model substrates in nymphs and adult males suggest that the microsomal monooxygenase systems are different between the two stages.