Abstract
Studies with an insect juvenile hormone mimic and the insecticide dieldrin have shown that enzymatic processes in the rumen reduce the epoxide moiety in these compounds to an olefin. This reaction is apparently microbial in origin and does not involve an observable intermediate. Epoxide reductions in the digestive tract of ruminants and possibly other mammals may be important in the detoxication of biologically active epoxides, including pesticides, alkylating agents, and carcinogens.