TY - JOUR
T1 - Development of oxidative stress by cytochrome P450 induction in rodents is selective for barbiturates and related to loss of pyridine nucleotide-dependent protective systems
AU - Dostalek, Miroslav
AU - Hardy, Klarissa D.
AU - Milne, Ginger L.
AU - Morrow, Jason D.
AU - Chen, Chi
AU - Gonzalez, Frank J.
AU - Gu, Jun
AU - Ding, Xinxin
AU - Johnson, Delinda A.
AU - Johnson, Jeffrey A.
AU - Martin, Martha V.
AU - Guengerich, F. Peter
PY - 2008/6/20
Y1 - 2008/6/20
N2 - 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), β-naphthoflavone (βNF), or clofibrate in a mouse model increased ROS parameters in the isolated liver microsomes, but isoniazid treatment did not. However, when F2-isoprostanes (F2-IsoPs) were measured in tissues and urine, PB showed the strongest effect and βNF 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 F2-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.
AB - 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), β-naphthoflavone (βNF), or clofibrate in a mouse model increased ROS parameters in the isolated liver microsomes, but isoniazid treatment did not. However, when F2-isoprostanes (F2-IsoPs) were measured in tissues and urine, PB showed the strongest effect and βNF 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 F2-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.
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U2 - 10.1074/jbc.M802447200
DO - 10.1074/jbc.M802447200
M3 - Article
C2 - 18442974
AN - SCOPUS:47749112410
SN - 0021-9258
VL - 283
SP - 17147
EP - 17157
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 25
ER -