absorption. However, oral nicotine metabolism has been demonstrated to be a worthwhile probe of CYP2A6 activity [14, 42] and it is not unreasonable to assert that the relative impact of different CYP2A6 alleles on first-pass metabolism is likely to translate well into their relative impact upon nicotine half-life during smoking. Indeed, the relative allele activities reported here do not substantially conflict with those determined by other in vivo protocols, and apparent differences are best explained by differences in genotyping and interpretation.
