Microsomal Oxidation and Insecticide Metabolism

Abstract

Once in the animal body, organic insecticides are subject to metabolism by a variety of enzymes. Depending on their chemical structure, the compounds may be hydrolyzed, oxidized, conjugated with endogenous metabolites, or otherwise modified. Of particular importance are reactions mediated by the oxidative enzymes known as microsomal oxidases, so called because of their localization in the microsomal fraction of cell homogenates. Since these enzymes as a class have an extremely broad spectrum of substrates and catalyze a wide variety of biotransformations, they play a central role in the metabolism of insecticides. In fact, most of the biodegradability of current insecticides is dependent on their successful biotransformation by microsomal oxidases of various species. These enzymes are also intimately associated with the phenomena of synergism, enzyme induction, and insecticide resistance.