Article date: March 2000
By: Mark R Welfare, Margaret F Bassendine, Ann K Daly, in Volume 49, Issue 3, pages 240-243
Aims To establish whether gender or N‐acetyltransferase 2 (NAT2) genotype influence the urinary 17 U+17X/137X ratio after dosing with caffeine.
Methods Ninety‐two nonsmoking individuals underwent caffeine phenotyping. NAT2 genotype was determined by the polymerase chain reaction followed by a restriction digest (PCR‐RFLP).
Results The median ratio for urinary 17 U+17X/137X was 6.7 (range 1.45–18.65). 55% of subjects were slow acetylators. Gender did not affect the metabolic ratio or NAT2 genotype. Mean 17 U+17X/137X ratio differed between fast (6.75) and slow (8.69) acetylators (95% CI for the difference, 0.32–3.56).
Conclusions The findings are further evidence that the 17 U+17X/137X urinary ratio is not a robust measure of CYP1A2 activity. A possible mechanism by which the ratio might be influenced by NAT2 genotype is suggested.
DOI: 10.1046/j.1365-2125.2000.00130.x
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