Prostaglandin D2 is a lipid-derived signaling hormone involved in inflammatory communication, allergic responses, sleep regulation, vascular signaling, and immune-cell coordination. PGD2 participates in local tissue responses during inflammation and plays important roles within respiratory tissues, nervous tissue, skin, and immune environments. It contributes to regulation of vascular tone, bronchial responsiveness, leukocyte recruitment, and inflammatory mediator signaling.
Within the nervous system, PGD2 also participates in sleep-associated signaling pathways and circadian neurophysiology. In immune tissues, mast cells are major producers of PGD2 during allergic and inflammatory activation. Depending on receptor subtype activation and tissue context, PGD2 can either amplify inflammatory signaling or participate in regulatory feedback processes that influence immune balance and tissue adaptation.
PGD2 is synthesized from arachidonic acid released from membrane phospholipids through phospholipase A2 activity. Cyclooxygenase enzymes convert arachidonic acid into prostaglandin H2 intermediates, which are then converted into PGD2 by prostaglandin D synthase enzymes.
Production occurs mainly in mast cells, macrophages, dendritic cells, brain tissue, respiratory epithelium, and additional inflammatory tissues. Unlike classical endocrine hormones stored in vesicles, PGD2 is synthesized rapidly on demand in response to cellular activation, immune signaling, or tissue stress. This allows localized and rapidly adjustable signaling responses.
PGD2 synthesis is regulated by inflammatory cytokines, allergen exposure, oxidative stress, phospholipase signaling pathways, immune-cell activation, and cyclooxygenase enzyme activity. Mast-cell degranulation strongly increases local PGD2 production during allergic and inflammatory responses.
PGD2 acts through DP1 and DP2 receptor pathways that influence cyclic AMP signaling, calcium regulation, leukocyte migration, vascular tone, and smooth muscle responsiveness. Enzymatic degradation pathways rapidly limit signaling duration and help maintain local tissue specificity. Through these integrated lipid-signaling systems, PGD2 contributes to inflammatory adaptation, allergic physiology, neuroendocrine sleep signaling, immune-cell coordination, and vascular regulation.
Locally acting eicosanoid from arachidonic acid that shapes allergic inflammation, vascular/bronchial tone, sleep, and adipose biology via DP1/DP2 receptors.
