ABSTRACT
This chapter presents an overview of the mechanisms involved in eicosanoid mobilization and metabolism in the polymorphonuclear leukocytes and of the biological activities of several of these fatty acids and of arachidonic acid and leukotriene B4 in particular. Leukotriene B4 production, and by implication arachidonic acid release, in neutrophils in response to a variety of stimuli has been reported. The 5-lipoxygenase catalyses the specific dioxygenation of arachidonic acid at position C-5 and initiates the synthesis of leukotrienes. The human platelet 12-lipoxygenase was the first mammalian lipoxygenase ever described, and platelets appear to be the only source of this enzyme in human blood cells. However, porcine blood neutrophils contain a very high level of 12-lipoxygenase activity. Several observations have suggested that among granulocytes, eosinophils are the major source of leukotriene C4 and 15-lipoxygenase products. Because of the putative roles of leukotrienes in human diseases, the regulation of leukotriene synthesis is the subject of extensive investigations.
