Prostaglandins are local mediators. There are biogenic amines (histamine), peptides (bradykinin), proteins (cytokines), but prostaglandins and leukotrienes include eicosanoids too. These molecules are responsible for the generation of inflammation and for the proper blood coagulation too
These are oxidized derivatives of 20 C polyunsaturated fatty acids; their precursors are eicosatetraenoic acid (arachidonic acid) and pentanoic acid.
Each cell can synthetise Prostanoids, but leukotrienes are less typycal.
Arachidonic acid is synthesized from linoleic and linolenic acid, solely esterified in cells glycerophospholipids, if spontaneously released, is immediately esterified. When arachidonic acid released by