Table 1.

Comparison of DNA adduct formation from 2′-hydroxylation vs 5′-hydroxylation of NNN in rats. Values for py-py-dI have been converted to fmol/mg DNA to match the reported POB-DNA adduct levels. Dosage and treatment length are detailed in the first column. Total POB-DNA adducts are the sum of O²-POB-thymidine, N⁷-POB-guanine, and O²-POB-cytosine. Adducts arising from 2′-hydroxylation predominate in all rat tissues, after accounting for dosage.

	Oral Cavity Mucosa	Esophageal Mucosa	Liver	Lung	Nasal Respiratory Mucosa	Nasal Olfactory Mucosa
Total py-py-dI Formation, (fmol/mg DNA) 50 ppm Racemic NNN, 3 weeks	21	85	37	383	574	302
Total POB-DNA Adduct Formation, (fmol/mg DNA) 10 ppm (R)-NNN, 2 weeks	205a	360b	70b	310b	2940a	851a
Total POB-DNA Adduct Formation, (fmol/mg DNA) 10 ppm (S)-NNN, 2 weeks	644a	1090b	340b	120b	1580a	201a
Total POB-DNA Adduct Formation, (fmol/mg DNA) 14 ppm (R)-NNN, 10 weeks	184c	736c	121c	704c	3250c	1700c
Total POB-DNA Adduct Formation, (fmol/mg DNA) 14 ppm (S)-NNN, 10 weeks	592c	2030c	728c	327c	6720c	431c

^aFrom Zhang et al. 2009.⁹

^bFrom Lao et al. 2007.⁷

^cFrom Zhao et al. 2013.¹⁰