title: Hemoprotein-dependent production of a neutrophil-activating factor from arachidonic acid.
abstract: Hemoproteins have been suggested to contribute to various forms of tissue injury by catalyzing the peroxidation of lipids. In this study, the ability of hemoglobin to catalyze the production of a neutrophil-activating factor from arachidonic acid was examined. Incubation of arachidonic acid, hydrogen peroxide, and hemoglobin at 37 degrees C for 30 min resulted in the production of a lipid-extractable substance that was chemotactic for neutrophils in vitro and could stimulate leukocyte adherence in vivo. These actions could be inhibited by two leukotriene B4 (LTB4) receptor antagonists. The peroxidation product cross-reacted significantly with an antibody directed against LTB4, but not with an antibody directed against LTC4. The production of this factor was hemoprotein dependent. Immunoreactive LTB4 and biological activity were produced only when hemoglobin, or another hemoprotein, cytochrome c, was present in the reaction mixture. The amount of the factor produced could be increased in a concentration-dependent manner by increasing the amounts of arachidonic acid or hydrogen peroxide in the reaction mixture. The production of this factor could be inhibited by 5-aminosalicylic acid, catalase, or deferoxamine. Separation of the lipid-extractable products of the peroxidation of arachidonic acid on high-performance liquid chromatography revealed that the immunoreactive (with anti-LTB4) and chemotactic substance had a retention time distinct from that of LTB4 and the hydroxyeicosatetraenoic acids. A lipid-extractable substance with significant cross-reactivity to anti-LTB4 could also be produced if plasma was substituted for arachidonic acid in the reaction mixture.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Gastrointestinal Research Group, Faculty of Medicine, University of Calgary, Alberta, Canada.
authors.forename: J L
authors.initials: JL
authors.lastname: Wallace
authors.forename: K P
authors.initials: KP
authors.lastname: Rioux
authors.forename: W
authors.initials: W
authors.lastname: McKnight
authors.forename: L
authors.initials: L
authors.lastname: Carter
authors.forename: D
authors.initials: D
authors.lastname: Jourd'heuil
authors.forename: J
authors.initials: J
authors.lastname: Meddings
authors.forename: B J
authors.initials: BJ
authors.lastname: Zimmerman
authors.forename: D N
authors.initials: DN
authors.lastname: Granger
authors.forename: M B
authors.initials: MB
authors.lastname: Grisham
mesh_terms: D000636:Aminosalicylic Acids / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D001798:Blood Proteins / Q000502:physiology*; D002630:Chemotactic Factors / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007975:Leukotriene B4 / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D019804:Mesalamine; D009504:Neutrophils / Q000502:physiology*; D051381:Rats
chemical_list: D000636:Aminosalicylic Acids; D001798:Blood Proteins; D002630:Chemotactic Factors; D007975:Leukotriene B4; D016718:Arachidonic Acid; D019804:Mesalamine; D006861:Hydrogen Peroxide