Table 3.

Effect of chronic nicotine consumption on NNK-induced lung tumor multiplicity and size in A/J micea

Tumors per mouseb (mean ± SD)
TotalDiameter, mm
GroupNTreatmentaMice with tumors, %<0.50.5–1.01.0–2.0>2
119No nicotine/saline310.53 ± 0.10.050.320.110.05
219Nicotine (0–46 wks)/saline260.32 ± 0.10.000.210.050.05
318No nicotine/NNK10018.4 ± 4.50.506.5010.11.39
418Nicotine (0–46 wks)/NNK10020.4 ± 5.40.287.8911.30.94
519Nicotine (0–2 wks)/NNKb10021.9 ± 5.30.807.9011.81.40
620Nicotine (2–46 wks)/NNKb10020.0 ± 5.40.555.8012.31.30
  • aThe protocol is illustrated in Fig. 1. Nicotine (0.44 μmol/mL) was administered in the drinking water for the time intervals indicated, and NNK (2 μmol) or saline was administered by intraperitoneal injection at 2 weeks. Twenty mice in each group were euthanized on day 18 for DNA adduct analysis, and the remaining mice (18–20) were euthanized at 46 weeks. One or two premature deaths occurred in groups 2 to 5, details are provided in Table 4. Because of a logistic error, only 19 animals were analyzed in group 1.

  • bThe number of total tumors per mouse ranged from 6 to 41.