Effects of smoking on benzo(alpha)pyrene- and glutathione-metabolizing enzymes in human lung tissue.

The influence of smoking on the metabolism of benzo(alpha)pyrene and glutathione was investigated in 190 patients with primary bronchial carcinoma and 20 patients with benign lung diseases. There were no significant differences in the activities of drug-metabolizing enzymes in the lung tissue of smokers, regardless of whether they smoked low- or high-tar and -nicotine cigarettes; former smokers; or nonsmokers; nor were there such differences between female and male patients. No significant differences existed between patients with squamous cell carcinoma and those with adenocarcinoma. Impaired detoxification due to decreased activity of glutathione S-transferases, rather induction of benzo(alpha)pyrene-metabolizing enzymes, may disturb the delicate balance between the generation and detoxification of reactive metabolites. This impairment may lead to the accumulation of these compounds in the cell.