Formation, Repair, and Genotoxic Properties of Bulky DNA Adducts Formed from Tobacco-Specific Nitrosamines

Table 3

Levels of 𝑂⁶-mG and 𝑂⁶-pobG in lung and livers of NNK-treated wild-type and AGT knockout mice^a [88].

	pmol adducts/𝜇mol guanine
AGT status	lung		liver
𝑂^6-mG	24 h	4 weeks	24 h	4 weeks
Wildtype	42±12	55±9	17±11	5.3±0.7
Knockout	65±19	110±20	210±110	380±80^b
𝑂^6-pobG
Wildtype	1.7±0.5	0.8±0.2	1.4±0.5	≤0.3
Knockout	2.9±0.6	2.5±0.3	2.7±1.2	4.9±1.4

aMice received either a single dose of NNK (∼250 mg/kg) and sacrificed 24 h postinjection or three weekly doses of NNK (∼250 mg/kg each week) and sacrificed 1 week after the third treatment. Numbers represent the average of five samples±SD.
bThree samples±SD. Two other samples were analyzed and these two animals had 𝑂⁶-mG levels of 26 and 31 pmol 𝑂⁶-mG/𝜇mol guanine. The liver 7-mG adduct levels for all five animals were similar: 134±17 pmol 7-mG/𝜇mol guanine.