RT Journal Article
SR Electronic
T1 Nitric Oxide and Acetaminophen-Mediated Oxidative Injury: Modulation of Interleukin-1-induced Nitric Oxide Synthesis in Cultured Rat Hepatocytes
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 1072
OP 1083
VO 282
IS 2
A1 Paul C. Kuo
A1 Rebecca A. Schroeder
A1 Joseph Loscalzo
YR 1997
UL http://jpet.aspetjournals.org/content/282/2/1072.abstract
AB The role of endogenous hepatocyte synthesis of nitric oxide (NO) in states of oxidative stress is largely unknown. In a model of rat hepatocytes in primary culture, NO production was induced by exposure to interleukin-1β (IL-1β, 50 ng/ml). Acetaminophen-mediated oxidative injury was analyzed in unstimulated and stimulated hepatocytes in the presence and absence of N-methyl-l-arginine, a substrate inhibitor of NO synthesis (100 μM). Inhibition of NO synthesis was associated with exacerbation of acetaminophen-mediated oxidative injury. This effect was independent of guanylyl cyclase and cytochrome P450 activity. In addition, oxidative stress was associated with augmentation of interleukin-1β-induced NO synthesis. Elevated NO synthesis occurred in parallel with increased inducible NO synthase (iNOS) enzyme activity and mass, steady-state levels of iNOS mRNA, increased transcription of the iNOS gene, and increased iNOS promoter activity. These effects were abrogated in the presence of antioxidants, suggesting that oxidative stress augments NO synthesis through a promoter-specific transcriptional regulatory mechanism. Thus, in conditions where oxidative injury may be a component of the overall proinflammatory state, induction of iNOS with subsequent elaboration of NO and augmentation of NO production may serve as an hepatoprotective mechanism against oxidative injury. The American Society for Pharmacology and Experimental Therapeutics