Inhibitory effect of LY 255283 on the synthesis of leukotriene B4 and thromboxane A2 in human peripheral blood polymorphonuclear leukocytes and monocytes

LY 255283 [(1-(5-ethyl-2-hydroxy-4-(6-methyl-6-)1H-tetrazol-5-yl)-heptyloxy) phenyl)ethanone], a specific leukotriene B(4) (LTB(4)) receptor antagonist, inhibited the production of LTB(4) in human peripheral blood polymorphonuclear leukocytes (PMNL) and in monocytes activated by calcium ionophore A23187. In human monocytes activated by ionophore it inhibited also the production of thromboxane B(2) (TXB(2)). The effect of LY 255283 on 5-lipoxygenase (5-LO) and LTA(4) hydrolase activities which catalyse the production of LTB(4) and LTA(4) has not been studied yet. It is thought that LY 255283 may inhibit the production of LTB(4) and TXA(2) by antagonising the effect of ionophore-induced LTB(4) on 5-lipoxygenase and cyclooxygenase in human peripheral blood PMNL and monocytes.