title: Interaction of reactive nitrogen and oxygen intermediates in HL60 and dimethylsulphoxide-differentiated HL60 cells.
abstract: The interaction of reactive nitrogen intermediates (RNI) with reactive oxygen intermediates (ROI) was inferred from the effect of added L-arginine on luminol-dependent chemiluminescence (LCL) and cytochrome C reduction in HL60 cells, dimethylsulphoxide (DMSO)-differentiated HL60 cells and human neutrophils. Phorbol myristate acetate (PMA)-stimulated HL60 cells had no effect on LCL and a decreased rate of cytochrome C reduction in the presence of increasing concentrations of L-arginine. Inhibition of L-arginine-mediated cytochrome C reduction was relieved by L-N(G)-monomethyl arginine (L-NMMA), an inhibitor of nitric oxide synthesis, in a concentration-dependent manner. In contrast, DMSO-differentiated cells and human neutrophils separated from blood showed decreased rates of LCL and cytochrome C reduction with increasing concentrations Of L-arginine, which were relieved to some extent by L-NMMA in a dose-dependent manner. These results are consistent with a 40% increase in the production of nitrate following stimulation of DMSO-differentiated cells and human neutrophils by PMA compared with only a 6% rise in undifferentiated HL60 cells. Possible inhibition of NADPH oxidase has been suggested to explain the responses of LCL, cytochrome C reduction and nitrate production by nitric oxide in the presence of L-arginine.
authors.affiliation: Division of Biochemistry and Molecular Biology, School of Life Sciences, The Australian National University, Canberra, Australia.
authors.forename: N
authors.initials: N
authors.lastname: Ahmed
authors.forename: M J
authors.initials: MJ
authors.lastname: Weidemann
mesh_terms: D002384:Catalysis; D002454:Cell Differentiation / Q000187:drug effects*; D003574:Cytochrome c Group / Q000378:metabolism; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D018922:HL-60 Cells; D006801:Humans; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D019255:NADPH Oxidases; D009569:Nitric Oxide / Q000096:biosynthesis / Q000378:metabolism; D009584:Nitrogen / Q000737:chemistry*; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species; D011956:Receptors, Cell Surface / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D003574:Cytochrome c Group; D017382:Reactive Oxygen Species; D011956:Receptors, Cell Surface; D009569:Nitric Oxide; D013482:Superoxide Dismutase; D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases; D009584:Nitrogen; D013755:Tetradecanoylphorbol Acetate; D004121:Dimethyl Sulfoxide