[Biotransformation in occupational medicine: the role of hepatic cytochrome P-450 in the mechanism of action and the biological monitoring of occupational toxic compounds].

Biotransformation is an important step in the investigation of occupational toxic chemicals. This is because the knowledge of the metabolic pathways and the enzymes involved in the activation and/or detoxication of xenobiotics may help in understanding the mechanism of toxicity and to rationalize the biological monitoring of exposed subjects. The largest enzymatic system involved in the biotransformation of industrial chemicals is cytochrome P-450, a family of haemoproteins capable of metabolizing a vast number of lipophilic, structurally different compounds. The study of the various metabolic reactions of this peculiar group of enzymes has greatly contributed to a) the clarification of the mode of action of several classes of occupational toxic and/or carcinogenic compounds, such as aromatic amines, polycyclic aromatic hydrocarbons, halogenated alkanes, benzene compounds and others, and b) the improvement of risk assessment in the biological monitoring of the exposed subjects, by allowing the toxicological significance (activation/detoxication) of single metabolites to be better understood.