Thromboxane A2 (TXA2) is a thromboxane. It is generated from prostaglandin H2 by thromboxane-A synthase. It is also a major component of blood clots. Aspirin irreversibly inhibits platelet cyclooxygenase 1 preventing the formation of prostaglandin H2, and therefore thromboxane A2.
TXA2 is very unstable in aqueous solution, since it is hydrolyzed within about 30 seconds to the biologically inactive thromboxane B2. Due to its very short half life, TXA2 primarily functions as an autocrine or paracrine mediator in the nearby tissues surrounding its site of production.
Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2.
Thromboxane is named for its role in clot formation (thrombosis).