calcimycin and 11-hydroxy-5-8-12-14-eicosatetraenoic-acid

To investigate the cooperation of chondrocytes and polymorphonuclear cells (PMN) in the biosynthesis of leukotrienes (LT).. PMN, resting and interleukin-1beta-stimulated cultured human chondrocytes, and mixtures of both cell types were incubated with A23187 and/or 14C-arachidonic acid (14C-AA). To explore the presence of LTC4 synthase and LTA4 hydrolase, the chondrocytes were incubated with authentic LTA4. Eicosanoids were analyzed using high performance liquid chromatography techniques.. Chondrocytes formed only prostaglandin E2 and minor amounts of 15-HETE and 11-HETE, the production of all of which was inhibited by 1 microM indomethacin. Incubation of PMN and chondrocytes produced more LTC4 from endogenous and exogenous AA, and more LTB4 from endogenous AA, than incubation of PMN alone, which was consistent with the presence of LTC4 synthase and LTA4 hydrolase activities in chondrocytes. Chondrocytes also slightly increased the level of PMN production of all 5-lipoxygenase (5-LO)-derived products from endogenous AA.. Human chondrocytes form eicosanoids from AA only by the cyclooxygenase pathway. Chondrocytes cooperate in the transcellular biosynthesis of LT since they possess LTA4 hydrolase and LTC4 synthase activities and increase metabolism by the 5-LO pathway in PMN.

Topics: Arachidonic Acid; Calcimycin; Cartilage, Articular; Cells, Cultured; Chondrocytes; Chromatography, High Pressure Liquid; Culture Media, Conditioned; Dinoprostone; Epoxide Hydrolases; Glutathione Transferase; Humans; Hydroxyeicosatetraenoic Acids; Indomethacin; Knee Joint; Leukotriene B4; Leukotriene C4; Neutrophils

Blood cells from the crab, Carcinus maenas, stimulated with calcium ionophore A23187, in the presence of exogenous fatty acid, produced cyclooxygenase, lipoxygenase and monooxygenase derivatives of eicosatetraenoic (20:4(n - 6)) and eicosapentaenoic (20:5(n - 3)) acids. Isolation, identification and quantification of these products was achieved using chiral and reverse phase-high performance liquid chromatography, gas-chromatography, radioimmunoassay and gas chromatography-mass spectrometry. The principle metabolites observed were 8-hydroxy fatty acids and 'E' series prostaglandins. Smaller amounts of thromboxane B2, 6-keto-prostaglandin F1 alpha and 5-, 9-, 11-, 12- and 15-hydroxy-eicosatetraenoic acids were also synthesised. Lipoxygenase, cyclooxygenase and cytochrome P-450 inhibitors were used to investigate the mode of product formation. Mixtures of hydroxy-fatty acid enantiomers were produced and the dominant chiral form varied with the position of the hydroxyl group. No leukotrienes or lipoxins were detected.

Topics: Animals; Arachidonic Acids; Blood Cells; Brachyura; Calcimycin; Chromatography, High Pressure Liquid; Cyclooxygenase Inhibitors; Eicosanoids; Enzyme Activation; Hemolymph; Hydroxyeicosatetraenoic Acids; Indomethacin; Masoprocol; Proadifen