Figure 1.
Synthesis of prostaglandins. Arachidonic acid is metabolized by the cyclooxygenase enzymes sequentially to PGG2 and then PGH2. The individual prostaglandin synthases convert PGH2 into the five primary prostanoids, PGD2, PGE2, PGF2α, PGI2, and TXA2. Each of these prostanoids signal through distinct G protein coupled receptors (GPCR).