[The role of enzymes of xenobiotic metabolism in the resistance of insects to insecticides].

The activity of three enzymatic systems of xenobiotic metabolism (cytochrome P-450-dependent monooxygenases, non-specific esterases and glutathione S-transferases) was studied in sensitive (S) and resistant to tetrametrin (Rtetr.), permetrin (Rperm.), mecarbenyl (Rmec.) and chlorophos (Rchlor.) strains of the housefly M. domestica L. In Rtetr. and Rmec., the activity of microsomal monooxygenases was increased 2.7- and 2.3-fold, respectively, as compared to S. The position of maxima of CO-difference spectra of cytochrome P-450 in all resistant strains (with the exception of Rchlor.) were shifted towards the short-wave region by 1-2 nm. The activity of glutathione S-transferase in Rtetr. was increased as compared to S. Analysis of the total esterase activity and electrophoresis in starch gel revealed quantitative and qualitative differences between the strains under study. In all resistant strains, except for Rmec., additional bands corresponding to the esterase activity were observed. The experimental results are discussed in terms of resistance of insects to insecticides.