Dostalek Miroslav, Hardy Klarissa D, Milne Ginger L, Morrow Jason D, Chen Chi, Gonzalez Frank J, Gu Jun, Ding Xinxin, Johnson Delinda A, Johnson Jeffrey A, Martin Martha V, Guengerich F Peter
Department of Biochemistry, Division of Clinical Pharmacology, and Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA.
J Biol Chem. 2008 Jun 20;283(25):17147-57. doi: 10.1074/jbc.M802447200. Epub 2008 Apr 28.
Reactive oxygen species (ROS) and oxidative stress have been considered in a variety of disease models, and cytochrome P450 (P450) enzymes have been suggested to be a source of ROS. Induction of P450s by phenobarbital (PB), beta-naphthoflavone (betaNF), or clofibrate in a mouse model increased ROS parameters in the isolated liver microsomes, but isoniazid treatment did not. However, when F(2)-isoprostanes (F(2)-IsoPs) were measured in tissues and urine, PB showed the strongest effect and betaNF had a measurable but weaker effect. The same trend was seen when an Nfr2-based transgene reporter sensitive to ROS was analyzed in the mice. This pattern had been seen earlier with F(2)-IsoPs both in vitro and in vivo with rats (Dostalek, M., Brooks, J. D., Hardy, K. D., Milne, G. L., Moore, M. M., Sharma, S., Morrow, J. D., and Guengerich, F. P. (2007) Mol. Pharmacol. 72, 1419-1424). One possibility for the general in vitro-in vivo discrepancy in oxidative stress found in both mice and rats is that PB treatment might attenuate protective systems. One potential candidate suggested by an mRNA microarray was nicotinamide N-methyltransferase. PB was found to elevate nicotinamide N-methyltransferase activity 3- to 4-fold in mice and rats and to attenuate levels of NAD(+), NADP(+), NADH, and NADPH in both species (20-40%), due to the enhanced excretion of (N-methyl)nicotinamide. PB also down-regulated glutathione peroxidase and glutathione reductase, which together constitute a key enzymatic system that uses NADPH in protecting against oxidative stress. These multiple effects on the protective systems are proposed to be more important than P450 induction in oxidative stress and emphasize the importance of studying in vivo models.
活性氧（ROS）和氧化应激已在多种疾病模型中得到研究，细胞色素P450（P450）酶被认为是ROS的一个来源。在小鼠模型中，苯巴比妥（PB）、β-萘黄酮（βNF）或氯贝丁酯诱导P450s会增加分离的肝微粒体中的ROS参数，但异烟肼处理则不会。然而，当在组织和尿液中测量F2-异前列腺素（F2-IsoPs）时，PB显示出最强的作用，βNF有可测量但较弱的作用。在小鼠中分析对ROS敏感的基于Nfr2的转基因报告基因时也观察到了相同的趋势。这种模式在大鼠的体外和体内研究中使用F2-IsoPs时也曾较早出现过（多斯塔莱克，M.，布鲁克斯，J.D.，哈迪，K.D.，米尔恩，G.L.，摩尔，M.M.，夏尔马，S.，莫罗，J.D.，和根杰里奇，F.P.（2007年）《分子药理学》72卷，第1419 - 页）。在小鼠和大鼠中发现的氧化应激体外 - 体内差异的一种可能性是，PB处理可能会削弱保护系统。mRNA微阵列提出的一个潜在候选基因是烟酰胺N - 甲基转移酶。发现PB可使小鼠和大鼠的烟酰胺N - 甲基转移酶活性提高3至4倍，并使两种动物体内的NAD(+)、NADP(+)、NADH和NADPH水平降低（20 - 40%），这是由于（N - 甲基）烟酰胺排泄增加所致。PB还下调了谷胱甘肽过氧化物酶和谷胱甘肽还原酶，它们共同构成了一个使用NADPH来抵御氧化应激的关键酶系统。这些对保护系统的多种影响被认为在氧化应激中比P450诱导更重要，并强调了研究体内模型的重要性。 （注：原文中“1419-1424”处有格式问题，推测可能是“1419 - 1424”，译文按此推测补充完整）
