Role of metabolism in short-term test development

The inherent or added capability for metabolism of chemicals to activate or inactivate intermediates has been a key in development of most of the tests used in genetic toxicology. The addition of an exogenous source of metabolism in the form of cell-free enzymes and their cofactors has aided in the design of most in vitro methods since 1971. Although it appears that this type of metabolic system will continue to be widely used in the future, new and potentially very useful techniques for carrying out metabolism will be added to those currently in use.