[Effect of prooxidants on nitric oxide formation in murine liver, treated with bacterial lipopolysaccharide]

Coinjection of citrate iron complex (7.5-10 mg iron/kg) with Escherichia coli lipopolysaccharide (LPS) inhibited generation of nitric oxide in the liver of mice caused by LPS-dependent synthesis of inducible NO-synthase (iNOS). Coinjection of hydroquinone, pyrogallol, or CCl4 with LPS also inhibited NO generation in the liver. Inhibition of LPS-dependent of NO synthesis in the liver by all these agents and iron can be due to their pro-oxidant effects on metabolism of this tissue. These pro-oxidants rapidly activate synthesis of low molecular weight antioxidants; LPS-dependently generated active oxygen forms in the liver of treated animals, which causes iNOS synthesis, are inactivated by the antioxidants; thus, accumulation of active oxygen species is decreased and iNOS synthesis is inhibited.