title: Leukotriene B4 costimulates 5-lipoxygenase activity in neutrophils via increased 5-lipoxygenase translocation.
abstract: The goal of this investigation was to assess the effect of leukotriene B4 (LTB4) on 5-lipoxygenase activity and to examine the possible mechanisms of this effect. Exogenous LTB4 significantly increased the release of endogenous LTB4 from A-23187-stimulated neutrophils. The 5-lipoxygenase product release from A-23187-stimulated neutrophils decreased in the presence of an LTB4 receptor antagonist, suggesting that LTB4 has a receptor-mediated, autocrine effect on 5-lipoxygenase activity. Neutrophil 5-lipoxygenase activity increased significantly as cell density increased. In the presence of exogenous LTB4, no significant change in [14C]arachidonic acid release from neutrophils was observed. Exogenous LTB4 increased the amount of immunoreactive 5-lipoxygenase protein detected in the nuclear fraction of disrupted cells. LTB4 receptor antagonism decreased the amount of immunoreactive 5-lipoxygenase detected in the nuclear fraction. Thus LTB4 exerts an autocrine, receptor-mediated, costimulatory effect on 5-lipoxygenase activity. This feedback appears to have biological significance and involves enhanced 5-lipoxygenase translocation to the nuclear membrane.
authors.affiliation: Department of Veterans Affairs Medical Center and Department of Medicine, University of California, San Diego 92161, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Serio
authors.forename: J R
authors.initials: JR
authors.lastname: Baker
authors.forename: W L
authors.initials: WL
authors.lastname: Ring
authors.forename: C A
authors.initials: CA
authors.lastname: Riddick
authors.forename: T D
authors.initials: TD
authors.lastname: Bigby
mesh_terms: D001094:Arachidonate 5-Lipoxygenase / Q000378:metabolism*; D016718:Arachidonic Acid / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D002452:Cell Count; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D007975:Leukotriene B4 / Q000494:pharmacology*; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D018102:Receptors, Leukotriene B4 / Q000037:antagonists & inhibitors; D013777:Tetrazoles / Q000494:pharmacology
chemical_list: D018102:Receptors, Leukotriene B4; D013777:Tetrazoles; D007975:Leukotriene B4; D016718:Arachidonic Acid; D001094:Arachidonate 5-Lipoxygenase; C063823:LY 255283