CAFFEINE AS A METABOLIC PROBE - EXPLORATION OF THE ENZYME-INDUCING EFFECT OF CIGARETTE-SMOKING
CAFFEINE AS A METABOLIC PROBE - EXPLORATION OF THE ENZYME-INDUCING EFFECT OF CIGARETTE-SMOKING
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DOI：
10.1038/clpt.1991.8
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发表时间：
1991-01-01
影响因子：
6.7
通讯作者：
TANG, BK
中科院分区：
文献类型：
--
作者：
KALOW, W;TANG, BK
最近人们认识到，人体咖啡因的初级代谢是由 P-450IA2 催化的，并且咖啡因的代谢速率可以根据单一尿液样本中的代谢比率来估计。包括 19 名吸烟者在内的 178 名学生接受了咖啡因测试，以确定他们的 P-450IA2 指数。两者都指出每天吸烟的数量和作为验证性指标的尿可替宁水平与酶活性显着相关，显示出剂量效应关系（分别为 r = 0.62 和 0.89）。然而，酶指数最高的非吸烟者多于吸烟者，这表明饮食元素或其他因素可能决定人群中的 P-450IA2 活性。由于 P-450IA2 是一种可能局限于肝脏的单加氧酶，咖啡因直接揭示了仅在肝脏中的 Ah 受体依赖性酶诱导，但它也可能是其他地方的诱导信号。
It has been realized recently that the primary metabolism of caffeine in humans is catalyzed by P-450IA2 and that the rate of caffeine metabolism can be estimated from a metabolic ratio in a single urine sample. A population of 178 students including 19 smokers were subjected to this caffeine test to establish their P-450IA2 index. Both stated numbers of cigarettes smoked per day and urinary cotinine levels as a confirmatory measure correlated significantly with enzyme activity showing dose-effect relationships (r = 0.62 and 0.89, respectively). Nevertheless, more nonsmokers than smokers had the highest enzyme indexes, suggesting that dietary elements or other factors may determine P-450IA2 activities in populations. Because P-450IA2 is a monooxygenase that may be confined to the liver, caffeine reveals directly the Ah-receptor-dependent enzyme induction only in the liver, but it may also be a signal of induction elsewhere.