The effect of human platelets with deficient lipoxygenase activities on leukotriene B4 (LTB4) synthesis by neutrophils was studied. When arachidonic acid (AA) metabolites obtained from the incubation of washed normal neutrophils and platelets with N-formylmethionylleucylphenylalanine (FMLP), cytochalasin B, and AA were analyzed by reversed-phase high-performance liquid chromatography, the synth...

The functional interrelationships between the cyclooxygenase and lipoxygenase systems for arachidonic acid metabolism in platelets have not yet been clarified. Although a number of specific inhibitors of the cyclooxygenase, such as aspirin and indomethacin, have been described, few inhibitors of the lipoxygenase have been found. Several hydroxy and hydroperoxy derivatives of arachidonic acid we...

Atherosclerosis may be viewed as an inflammatory disease process that includes early oxidative modification of LDLs, leading to foam cell formation. This "oxidation hypothesis" has gained general acceptance in recent years, and evidence for the role of lipoxygenases in initiation of, or participation in, the oxidative process is accumulating. However, the relative contribution of macrophage-exp...

15-Hydroxyeicosatetraenoic acid (HETE), as a mammalian biologically active metabolite, has anticarcinogenic effect. The conditions of producing 15-HETE from arachidonic acid by using soybean lipoxygenase were optimal at pH 8.5 and 20°C with 9 g/l arachidonic acid, 54.4 U/ml soybean lipoxygenase, and 4% methanol. Under these optimized conditions, the enzyme produced 9.5 g/l 15-HETE after 25 min,...

A homogenate of epidermal cells isolated from human skin converted arachidonic acid to 12S-hydroxy-5, 8,10,14-eicosatetraenoic acid and 15-hydroxy-5, 8,11,13-eicosatetraenoic acid as the main lipoxygenase products. The production of these hydroxy acids was not stimulated by the addition of 1 mM NADPH required for cytochrome P-450 reaction, but inhibited by 65-75% with 40 microM nordihydroguaiar...

Abbreviations: 12/15-LOX, 12/15-lipoxygenase; 5-LOX, 5-lipoxygenase; 5/12/15(S)HETE , 12/15(S)-hydroxyeicosatetraenoic acid; 13(S)-HODE, 13(S)hydroxyoctadecadienoic acid; LxA4, lipoxin A4; STAg, soluble toxoplasma antigen; ICSBP, Interferon Consensus Sequence Binding Protein; IRF-8, Interferon Regulatory Factor-8, BMNCs, Brain Mononuclear Cells Copyright © 2009, American Society for Microbiolog...

The influence of the leukotoxin of Pasteurella haemolytica on the generation of arachidonic acid metabolites by bovine polymorphonuclear leukocytes (PMNs) was investigated. PMNs released 5-, 12-, and 15-hydroxyeicosatetraenoic acids (5-, 12-, and 15-HETE) and leukotriene B4 (LTB4) upon stimulation with arachidonic acid. The leukotoxin preparations dose dependently enhanced the release of the 5-...

OBJECTIVE Aortic 15-lipoxygenase (15-LO) metabolizes arachidonic acid (AA) to 15-hydroperoxyeicosatetraenoic acid, which is then converted to the vasodilators 15-hydroxy-11,12-epoxyeicosatrienoic acid and 11,12,15-trihydroxyeicosatrienoic acid. These metabolites contribute to endothelium-dependent relaxations of rabbit aorta to AA and acetylcholine. We investigated the identity of rabbit aortic...