title: Production of an arginine-derived relaxing factor induced by IFN-gamma plus endotoxin in murine adenocarcinoma EMT 6 cells.
abstract: Treatment of EMT 6 mammary adenocarcinoma cells with Interferon-gamma (IFN-gamma, 10 U.ml-1) plus endotoxin lipopolysaccharide (LPS, 100 ng.ml-1) induces concomitantly a growth arrest and production of citrulline and nitrite from L-arginine. A similar L-arginine-dependent metabolism is responsible for the vascular smooth muscle relaxing effect of stimulated endothelial cells. We therefore investigated the ability of EMT 6 cells to induce the relaxation of endothelium-denuded rat aortic rings precontracted with noradrenaline (1 microM). Pretreatment of EMT 6 cells with IFN-gamma + LPS increased their relaxing potency by 5-10 times. The relaxin effects of control and treated EMT 6 cells were entirely counteracted by NG-monomethyl-L-arginine (300 microM), a specific inhibitor of nitrite and citrulline production from L-arginine, and by methylene blue (10 microM) and LY 83583 (10 microM), two inhibitors of NOo-induced activation of guanylate cyclase. The effect of NG-monomethyl-L-arginine was reversed by L- but not D-arginine (1 mM). It is concluded that IFN-gamma + LPS increase the production of a relaxing factor in EMT 6 cells through the L-arginine-NOo-synthase pathway.
authors: Laboratoire de Biochimie- Biophysique, CNRS URA 1116, Université de Paris 11, Orsay, France.
authors: J F
authors: JF
authors: Petit
authors: C
authors: C
authors: Schott
authors: M
authors: M
authors: Lepoivre
authors: J C
authors: JC
authors: Stoclet
mesh_terms: D000230:Adenocarcinoma; D000634:Aminoquinolines / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000502:physiology; D001120:Arginine / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004731:Endotoxins / Q000494:pharmacology*; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology; D009569:Nitric Oxide / Q000096:biosynthesis* / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011994:Recombinant Proteins; D013189:SRS-A / Q000037:antagonists & inhibitors; D014664:Vasodilation / Q000187:drug effects; D019323:omega-N-Methylarginine
chemical_list: D000634:Aminoquinolines; D004731:Endotoxins; D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D013189:SRS-A; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D007371:Interferon-gamma; C041715:6-anilino-5,8-quinolinedione; D001120:Arginine