Thromboxane

Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2. The distinguishing feature of thromboxanes is a 6-membered ether-containing ring.

Thromboxane is named for its role in clot formation (thrombosis).

Production

Thromboxane-A synthase, an enzyme found in platelets, converts the arachidonic acid derivative prostaglandin H₂ to thromboxane.

Mechanism

Thromboxane acts by binding to any of the thromboxane receptors, G-protein-coupled receptors coupled to the G protein G_q.

Functions

Thromboxane is a vasoconstrictor and a potent hypertensive agent, and it facilitates platelet aggregation.

It is in homeostatic balance in the circulatory system with prostacyclin, a related compound. The mechanism of secretion of thromboxanes from platelets is still unclear. They act in the formation of blood clots and reduce blood flow to the site of a clot.

Role of A2 in platelet aggregation

Thromboxane A₂ (TXA₂), produced by activated platelets, has prothrombotic properties, stimulating activation of new platelets as well as increasing platelet aggregation.