Fig. 4

Graphic scheme of pathways shared by genes found in network analysis for progressive motility. Only part of the cyclooxygenase pathway is presented. Cytosolic phospholipase A2 group IVA (PLA2G4A) is involved in cleaving arachidonic acid from phospholipids, preferentially (I). Then, the free arachidonic acid is metabolized to produce eicosanoids (including prostaglandins) in the process known as cyclooxygenase pathway (II–V). The genes prostaglandin-endoperoxide synthase 2 (PTGS2/COX-2, number II) and hematopoietic prostaglandin D synthase (HPGDS, number III) are involved in this pathway. The COX-2 enzymes catalyze prostaglandin H₂ (PGH₂) synthesis from arachidonic acid (II), providing PGH₂ for the action of HPGDS (III) and production of prostaglandin D₂ (PGD₂) in testes interstitial mast cells. PGH₂ can also be converted into prostaglandin E₂ (PGE₂, number IV) and prostaglandin F_2α (PGF_2α, number V)