Nitric oxide generation from extracellularly applied NG-hydroxy-L-arginine in LPS-activated RAW 264 macrophages.
Lipopolysaccharide (LPS)-activated but not control RAW 264 macrophages produced nitric oxide (NO) from extracellularly-applied NG-hydroxy-L-arginine (L-NOHA) in a concentration-dependent manner, as measured by EPR spin trapping and assays for NO2- and NO3-. This production was inhibited by NG-nitro-L-arginine methyl ester and NG-monomethyl-L-arginine, NO-synthase inhibitors, as well as by L-lysine, a competitor for the y+ amino acid carrier system. No significant differences were found between L-NOHA and L-arginine with respect to the rate of NO production and the effects of inhibitors. These results provide evidence that extracellular L-NOHA can enter LPS-activated RAW 264 macrophages via a cationic amino acid carrier system and be metabolized to NO by NO-synthase. The data also suggest that no alternative pathway exists for NO production from L-NOHA in non-activated RAW 264 macrophages.
Vetrovsky
P
P
Laboratoire de Pharmacologie et de Physiopathologie Cellulaires-CNRS URA600, Faculté de Pharmacie, Université Louis Pasteur de Strasbourg, Illkirch, France.
Kleschyov
A L
AL
Entlicher
G
G
Poindron
P
P
Stoclet
J C
JC
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002460:Cell Line; D004578:Electron Spin Resonance Spectroscopy; D008070:Lipopolysaccharides; D008239:Lysine / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors
D008070:Lipopolysaccharides; D009569:Nitric Oxide; C068309:N(omega)-hydroxyarginine; D001120:Arginine; D019001:Nitric Oxide Synthase; D008239:Lysine