title: Cell damage unmasks 15-lipoxygenase activity in human neutrophils.
abstract: Metabolism of arachidonic acid (10 microM) into 15(S)-hydroxyl-5,8,11-cis-13-trans-eicosatetraenoic acid (15-HETE) was proportional to lactate dehydrogenase release from human neutrophils incubated with supratherapeutic concentrations of non-steroidal anti-inflammatory agents. In contrast to others (Vanderhoek, J., and Bailey, J. (1984) J. Biol. Chem. 259, 6752-6756), we report that increased 15-HETE formation was not uniquely attributable to 5 mM ibuprofen, and it did not originate from enzymatic activation. For instance, ibuprofen (1-5 mM) did not affect the isolated 15-lipoxygenase enzyme in the 100,000 X g supernatant from neutrophil lysates, and dose-dependent increases in 15-HETE biosynthesis, proportional to lactate dehydrogenase release, were evident with benoxaprofen, naproxen, flurbiprofen, or etodolac. At similar supratherapeutic concentrations (1-5 mM), aspirin and phenylbutazone did not influence lactate dehydrogenase release or 15-HETE production. In further contrast, neutrophils did not tolerate 1-5 mM ibuprofen. Biochemical, morphological, flow cytometric, and fluorochromatic analyses each indicated cytological damage. A correlation between lactate dehydrogenase release and increased 15-HETE formation was a dose-dependent property also exhibited by arachidonic acid alone (10-100 microM). We conclude that cytological damage, facilitating access of arachidonic acid to 15-lipoxygenase in a cytosolic compartment, accounts for this phenomenon.
authors.forename: J
authors.initials: J
authors.lastname: McGuire
authors.forename: J
authors.initials: J
authors.lastname: McGee
authors.forename: N
authors.initials: N
authors.lastname: Crittenden
authors.forename: F
authors.initials: F
authors.lastname: Fitzpatrick
mesh_terms: D000085:Acetates / Q000494:pharmacology; D001091:Arachidonate Lipoxygenases; D001241:Aspirin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D017308:Etodolac; D005470:Fluorometry; D005480:Flurbiprofen / Q000494:pharmacology; D006801:Humans; D006893:Hydroxyeicosatetraenoic Acids / Q000097:blood; D007052:Ibuprofen / Q000494:pharmacology; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008084:Lipoxygenase / Q000097:blood*; D009288:Naproxen / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology*; D010653:Phenylbutazone / Q000494:pharmacology
chemical_list: D000085:Acetates; D006893:Hydroxyeicosatetraenoic Acids; D017308:Etodolac; D009288:Naproxen; D005480:Flurbiprofen; C025984:15-hydroxy-5,8,11,13-eicosatetraenoic acid; D007770:L-Lactate Dehydrogenase; D001091:Arachidonate Lipoxygenases; D008084:Lipoxygenase; D010653:Phenylbutazone; D001241:Aspirin; D007052:Ibuprofen