Hydroxylamine is a vasorelaxant and a possible intermediate in the oxidative conversion of L-arginine to nitric oxide

Eugene G. DeMaster, Leopoldo Raij, L. Archer Stephen, E. Kenneth Weir

Research output: Contribution to journalArticle

80 Scopus citations

Abstract

Our objective was to determine whether hydroxylamine is a possible intermediate in the oxidative conversion of L-arginine to nitric oxide. Vasorelaxation by hydroxylamine is known to be mediated by nitric oxide. The vasorelaxant properties of hydroxylamine were examined using rat aortic rings and an isolated rat lung perfusion model. Hydroxylamine and acetylcholine were equally effective in relaxing norepinephrine-contracted intact aortic rings, whereas only hydroxylamine relaxed aortic rings with endothelium removed. This endothelium-independent vasorelaxation by hydroxylamine indicated that the hydroxylamine-converting enzyme is not localized solely within endothelial cells. Catalase, an enzyme known to oxidize hydroxylamine to nitric oxide, was present in homogenates of intact and endothelium-denuded rings. Cyanamide, another catalase substrate and a known precursor of nitroxyl (HNO), was not a vasorelaxant of aortic rings or of isolated, hypoxia-constricted lungs. These results suggest that free nitroxyl is not an intermediate in the oxidation of hydroxylamine to nitric oxide. An overall pathway for the oxidative conversion of L-arginine through an hydroxylamine intermediate to nitric oxide is proposed.

Original languageEnglish (US)
Pages (from-to)527-533
Number of pages7
JournalBiochemical and biophysical research communications
Volume163
Issue number1
DOIs
StatePublished - Aug 30 1989

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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