Thromboxane
Chapter: 2
A group of eicosanoids that are produced from arachidonic acid by the action of cyclooxygenase. The principal proinflammatory mediator in the group is the highly unstable TXA2, which is known for its potency as an aggregator of platelets and as a cause of mediator release from their granules. It is also a vasoconstrictor. Thromboxanes are, thus, the physiologic antagonists of prostacyclin (PGI2; see separately). An imbalance between the two, in the favor of thromboxane, will lead to initiation of platelet aggregation and an acute inflammatory response (fig. 2-13, text). The thromboxanes, together with the prostaglandins, make up the prostanoid subgroup of the eicosanoids.