The metabolism of insecticides: the role of monooxygenase enzymes.

In summary, it can be said that advances have been made in understanding the range and significance of monooxygenase reactions involving insecticides in both target and non-target species and that some specific aspects emerge that should command the attention of insecticide toxicologists and others in the immediate future. The role of co-oxidation of insecticides during prostaglandin synthesis has just emerged as an issue but, if we can extrapolate from other xenobiotics (126), we can predict with some confidence that it will assume major proportions. It is also apparent that both activation and detoxication reactions are catalyzed by the FAD-containing monooxygenase and that many of these reactions were formerly attributed to the cytochrome P-450-dependent monooxygenase system. Since any particular substrate may be oxidized by either or both of these two routes, it is essential that studies be conducted to define their relative contributions to xenobiotic oxidation in microsomal preparations and ultimately in vivo. The area of interactions and the mechanisms behind them is also of importance, from the public health point of view in the case of multiple exposures, and from the practical viewpoint in the case of insecticide synergists. While the above aspects are not the only ones of future importance, they should contribute to the ultimate goal of insecticide toxicology: practical, safe use of chemicals for the control of insect pests.