Fig. 4.

Nicotine and NNK induce γ-OH-PdG and O⁶-medG in cultured human lung and bladder epithelial cells. Human lung epithelial (BEAS-2B) cells and urothelial (UROtsa) cells were treated with different concentrations of nicotine and NNK as described in text. O⁶-medG and PdG formed in the genomic DNA were determined as described in Fig. 1. (A) The DNA adducts were detected by immunochemical methods (13, 28). (B) The PdG adducts formed in the genomic DNA were further identified as γ-OH-PdG adducts by the ³²P postlabeling followed by 2D-TLC/HPLC method (13, 28).