Reactive eicosanoid intermediates and transcellular biosynthesis

Most of the studies conducted in the seventies as well as in the early eighties, have been designed to establish the oxidative pathways of arachidonic acid by specific cell types resulting in the determination of the structure of eicosanoids by a given cell. Such an approach has delineated specific enzymatic patterns by certain cells in the blood and vascular system. Such findings are summarized in Table I. Platelets produce mainly 12-hydroxyeicosatetraenoic acid, 12-hydroxy heptadecatrienoic acid and thromboxane A2. Endothelial cells from human umbilical cord or vascular smooth muscle synthesize mainly prostaglandin I2 (prostacyclin) and prostaglandins E2 and F2α whereas this production is different for endothelial cells from the microvasculature. Polymorphonuclear granulocytes synthesize nearly exclusively LTB4 and eosinophils generate LTC4. Monocytes, depending upon their origin or their maturation, seem to produce both leukotrienes. In contrast, red blood cells and lymphocytes lack the specific oxygenases to form eicosanoids.