Dichlorodiphenyltrichloroethane (DDT)

 DDT (dichlorodiphenyltrichloroethane) is a colorless, crystalline, tasteless and almost odorless organochloride known for its insecticidal properties. In insects it opens sodium ion channels in neurons, causing them to fire spontaneously, which leads to spasms and eventual death. Insects with certain mutations in their sodium channel gene are resistant to DDT and other similar insecticides. DDT resistance is also conferred by up-regulation of genes expressing cytochrome P450 in some insect species,[18] as greater quantities of some enzymes of this group accelerate metabolism of the toxin into inactive metabolites—in essence, these enzymes are natural antidotes to the poison. Potential mechanisms of action on humans are genotoxicity and endocrine disruption. DDT can be directly genotoxic, but may also induce enzymes to produce other genotoxic intermediates and DNA adducts.