HUMAN ANATOMY AND PHYSIOLOGY

 PROSTACYLINS THROMBOXANE AND LEUKOTRIENES

These substances have been recently discovered as the intermediates or the end - products of the different pathways in prostaglandin synthesis prostacyclin is nothing but PGI2 and is synthesized as an intermediate of PGE2 with the help of enzyme prostacyclin synthetase Thromboxane A2 is synthesized from PGH2 with the help of thromboxane synthetase in another pathway lipoxygenase converts arachidonic acid to another compound called leukotrienes the name leukotrienes has come because they were first discovered in leucocytes one of the leucotriene is a 5- hydroxy derivative conjugated with glutathione this is nothing but an age old autacoid slow releasing substance -A(SRS-A) 

Thromboxane ::

promotes platelet aggregation and produces vasoconstriction Dazoxiben is an agent that inhibits thromboxane synthesis by inhibiting the enzyme thromboxane synthetase this may therefore turnout to be an-important and useful anti thrombotic agent 

prostacyclins:: 

prostacyclins are having actions opposite to thromboxane they inhibit platelet aggregation and produce vasodilatation they are potential agents to be used as antithrombotic agent 

Leukotrienes::

leukotrienes are very new compounds and their pharmacological action are still not established LTC4 and LTD4  produce powerful bronchoconstriction these agents are chemotactic for neutrophils (WBC) 

and possibly play an important role in the process of inflammation