Prostaglandin-H2 D-Isomerase (PTGDS) belongs to the Lipocalin family of calycin superfamily. PTGDS is preferentially expressed in the brain. PTGDS catalyzes the conversion of PGH2 to PGD2, a prostaglandin involved in smooth muscle contraction/relaxation and a potent inhibitor of platelet aggregation. PTGDS is involved in a variety of CNS functions, such as sedation, REM sleep and PGE2-induced allodynia, and may have an anti-apoptotic role in oligodendrocytes. PTGDS binds small non-substrate lipophilic molecules and may act as a scavenger for harmful hydrophopic molecules and a secretory retinoid and thyroid hormone transporter. It possibly participates in development and maintenance of the blood-brain, blood-retina, blood-aqueous humor, blood-testis barrier, the central nervous system and male reproductive system.
