Mammalian lipoxygenases have been implicated in inflammation and atherosclerosis and, thus, lipoxygenase inhibitors may be of pharmacological interest. In cells, lipoxygenases occur in a catalytically silent ground state that requires activation to become active. We found that the seleno-organic drug ebselen [2-phenyl-1, 2-benzisoselenazol-3(2H)-one], which exhibits anti-inflammatory properties...

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...

Lipoxygenase activity was measured in human platelet subcellular fractions. From a sonicated platelet preparation, a granule fraction, mixed membranes (surface and intracellular) and cytosol fractions were separated by differential centrifugation. With respect to activities in the sonicated preparation, the lipoxygenase was slightly enriched in both the cytosol and mixed-membrane fractions and ...

When human neutrophils, prelabeled with [3H]arachidonic acid, were incubated with 5S,15S-dihydroxyeicosatetraenoic acid (5,15-diHETE), a dose-dependent increase in the 15-lipoxygenase product [3H]-15-HETE was observed relative to untreated cells. Typically, a fivefold increase in [3H]-15-HETE formation was obtained upon exposure of these cells to 3 muM 5,15-diHETE. There was no appreciable enha...

The complete amino acid sequence of arachidonate 12-lipoxygenase (EC 1.13.11.31) of porcine leukocytes was deduced by cloning and sequence analysis of DNA complementary to its mRNA. The sequence was confirmed by automated Edman degradation of the N-terminal regions of the native enzyme and its proteolytic fragments. The cDNA had an open reading frame encoding 662 amino acid residues with a calc...

The lipid fluidity of microsomal membranes from the petals of cut carnation flowers decreases as the flowers senesce. A comparable change in fluidity was induced by in vitro aging of microsomal membranes from young flowers under conditions in which membranous lipoxygenase-like activity was active. There was no change in fluidity when the membranes were aged in the presence of inhibitors of lipo...

We examined the mechanism of arachidonic acid-induced vasodilation in rat small mesenteric arteries and determined the primary arachidonic acid metabolites produced by these arteries. Responses to arachidonic acid in small mesenteric arteries from Sprague-Dawley rats were investigated in vitro in the presence or absence of endothelium or after pretreatment with inhibitors of nitric oxide (NO), ...

Rat pancreatic islets incubated in nutrient medium were used to study the role of endogenous arachidonic acid metabolism in pancreatic hormone secretion. Both glucose and fetal calf serum stimulated radioimmunoassayable PGE2 production and insulin secretion from islets. These effects were abolished by the phospholipase inhibitor p-bromophenacyl bromide or by concurrent inhibition of cyclooxygen...

salicylic acid (sa) is considered to be plant signal molecule that plays a key role in plant growth, development, and defense responses. the physiological mechanism of exogenous sa to affect the senescence of cut lisianthus flowers during vase life was investigated. fresh cut lisianthus flowers were treated with distilled water (control), 0.5, 1 and 2 mm sa and then held at 25◦c up to 12 days. ...

Oxidized low density lipoprotein (LDL) possesses several atherogenic properties. The mechanisms by which LDL becomes oxidized in vivo remain unknown, but previous studies have suggested that 15-lipoxygenase may be one of the factors involved in the initiation of LDL oxidation in the arterial wall. 3 wk after a retrovirus-mediated 15-lipoxygenase gene transfer into iliac arteries of normocholest...