| 20 | 4 | 5Z,8Z,11Z,14Z  | CAS 506-32-1  | is present in animal visceral fat (brain, liver, kidney, lung, spleen), and is a -tetra-unsaturated fatty acid. I caused by the decomposition of cell membrane in the phospholipid. Prostaglandin, and important as starting materials for the thromboxane, leukotriene such as are known as a series of metabolic pathway to give eicosanoids, arachidonic acid cascade are compounds