Smoking-related DNA adducts: 32P-postlabeling analysis of 7-methylguanine in human bronchial and lymphocyte DNA.

7-methylguanine DNA adducts were determined in macroscopically normal bronchial specimens and peripheral blood lymphocytes of 20 patients undergoing pulmonary surgery. A recently developed 32P-postlabeling assay was applied with anion exchange chromatography as an adduct enrichment method. The material consisted of 13 smokers and 7 non-smokers. The mean bronchial 7-methylguanine levels of 11 smokers and 6 non-smokers were 17.3 and 4.7 adducts/10(7) nucleotides. In lymphocyte DNA, the respective mean levels were 11.5 and 2.3 adducts/10(7) nucleotides. The bronchial DNA adduct levels in smokers were statistically higher than those in non-smokers. Among 5 smokers, for whom both bronchial and lymphocyte DNA was available, 7-methylguanine levels correlated in the two tissues (r = 0.77).