A short review of the problems posed by xenobiotics in chemical mixtures and the role of mixed function oxidases

This short review presents an indication of the health and environmental problems posed by exposure to the steadily increasing presence of xenobiotic compounds. Investigations and previous reviews, which dealt with the functions of cytochrome P450-Mixed Function Oxidases with particular reference to their actions on chemical mixtures, are evaluated in detail. Special attention is also directed to investigations which deal with the evaluation of the toxicity of chemical mixtures. The ever increasing quantity and variety of chemical compounds to which the public is inevitably exposed, makes it obvious that for effective evaluation of health effects due to chemical mixtures the classical toxicological methods, which only focus on the toxicity of individual chemicals, are inappropriate. Chemical mixtures may produce additive, synergistic or also antagonistic effects due to the induction and action of Mixed Function Oxidases. Hence it is essential to consider the overall exposure to chemicals in evaluating the effects of chemical mixtures on public health and on the ecology.