Main Article Content
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment
and originated from incomplete combustion process of organic materials. This
compounds are bioactivated to reactive metabolites which bind covalently to DNA
initiating carcinogenesis. PAHs have been well established as an enzyme inducer of
cytochrome P450 (CYP) such as CYP1A1 and CYP1A2. Caffeine is primarily
metabolized by CYP1A2 to paraxanthine, so it has been used as a specific probe for
assessing CYP1A2 activity. The purpose of this study was to compare CYPIA2
activity in female subjects between smoke and non- smoke exposure using serum
paraxanthine/caffeine ratio. Each subject took a 180 mg single oral dose of caffeine
solution. Blood samples were collected before and 5 hours after caffeine intake. The
serum was separated by centrifugation and stored at -20 °C until analysis by HPLC.
Carbonmonoxide (CO) level in blood was also detected using spectrophotometer. The
results showed that serum paraxanthine/caffeine ratio in exposed subjects was
significantly higher than non-exposed subjects (mean ± SD of 0.45 ± 0.18 and 0.33 ±
0.12, respectively; P< 0.05). CO level in exposed subjects was also significantly
higher than non-exposed subjects (mean ± SD of 4.02 ± 0.83 and 3.00 ± 0.72,
respectively, P< 0.05). Conclusion: By using paraxanthine/caffeine ratio as a probe,
CYP1A2 activity is increased in smoke exposed subjects. The result implies that these
subjects has exposed to PAHs and has more risk of carcinogenesis.
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