INTERACTIONS OF XENOBIOTICS IN THE RESPIRATORY-TRACT FOLLOWING NONINHALATION ROUTES OF EXPOSURE

Compounds of highly variable structure may induce toxic effects and tumours in the respiratory tract following peroral or parenteral administration in experimental animals. Such compounds are used in industrial processes or may be present in the food as contaminants or pesticide residues. This review gives examples of selective metabolism and toxicity of chemicals in different segments of the respiratory tract. Many of these compounds require metabolic activation to exert toxicity. Accordingly, the susceptibility of the respiratory tract to the effects of such agents may be influenced by other compounds modulating the activity of activating xenobiotic metabolizing enzymes. Dietary factors may alter the susceptibility to experimental lung carcinogenesis also via other mechanisms. As concluded from experimental data, the human lung may be exposed to a wide array of potentially toxic compounds present in the diet or the environment. Such exposures may constitute confounding factors in low-risk lung cancer epidemiology. © 1990 Oxford University Press.