Exhaled Breath Condensate: A Promising Source for Biomarkers of Lung Disease

Figure 2

Metabolism of arachidonic acid. Arachidonic acid is released from phospholipids by the action of phospholipase A2 (PLA2). Arachidonic acid is metabolized by cyclooxygenases (COXs), lipoxygenases (LOXs), and cytochrome P450 (CYP). COXs metabolize arachidonic acid to prostaglandins (PGs), prostacyclin (PGI2), and thromboxanes (TXs). Leukotrienes (LTs) are the final arachidonic acid metabolites in the 5-lipoxygenase- (5-LO-) mediated pathway. CYP epoxygenases (CYP-EO) metabolize arachidonic acid to epoxyeicosatrienoic acid (EETs), and CYP hydroxylases (CYP-HO) metabolize arachidonic acid to hydroxyeicosatetraenoic acids (HETEs). 8-Isoprostane (8-IP) can be generated in vivo by the free radical-catalyzed peroxidation of arachidonic acid.