Abstract
The synthesis and release of leukotriene B 4 (LTB 4) from canine polymorphonuclear leukocytes (PMNs) was characterized in terms of incubation time, temperature and effects of calcium ionophore A23187 concentrations. Maximal LTB 4 concentrations were determined when canine PMNs were incubated with 10 μM A23187. Increasing LTB 4 concentrations were determined through 10 min incubation. The maximal LTB 4 concentrations ( 310 ± 30 pg LTB 4 2.5 × 10 5 cells ) determined at 10 min did not change through a 55 min incubation period. Greater LTB 4 concentrations were synthesized by canine PMNs at 37°C ( 268 ± 12 pg LTB 4 2.5 × 10 5 cells ) than at 25°C ( 206 ± 11 pg LTB 4 2.5 × 10 5 cells ) or 5°C ( 59 ± 3 pg LTB 4 2.5 × 10 5 cells ). The synthesis of LTB 4 in canine PMNs was inhibited by incubation of the cells with either of two known lipoxygenase inhibitors, BWA4C or BW755C. BWA4C inhibited LTB 4 synthesis with an approximate IC 50 = 0.1 μM, whereas BW755C inhibited LTB 4 synthesis with an approximate IC 50 = 10 μM. These results indicate canine PMNs have the capability to synthesize large quantities of LTB 4 when stimulated with calcium ionophore A23187. Furthermore, the 5-lipoxygenase inhibitors BWA4C, an acetohydroxyamic acid, and BW755C, a phenyl pyrazoline, can readily inhibit LTB 4 synthesis in canine PMNs.
Published Version
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