Isoprostanes are formed from archidonic acid by ?

Ans. is 'd' i.e., Non-enzymatic free radical peroxidationEpoxygenase pathway Cytochrome P450 may conve arachidonic acid (AA) to 20-HETE (20-hydroxyeicosa tetraenoic acid) or EET (epixyeicosatrienoic acid).EET may function as endothelium derived hyperpolarization factor paicularly in coronary circulation. It also possesses anti-inflammatory, anti-apoptotic and pro-angiogenic action. Biological effects of EET are reduced by metabolism to less active DHET with the help of epoxide hydrolase.20 HETE causes vasoconstriction of renal aeries and has been implicated in the pathogenesis of hypeension. In contrast, EET possesses antihypeensive propeies its vasodilating and natriuretic actions. Inhibitors of epoxide hydralase (results in elevated levels of EET) are being developed as antihypeensive drugs.Isoeicosanoid pathway Isoprostanes are formed by non-enzymatic free radical based peroxidation of arachidonic acid.Iso prostanes have potent vasoconstrictor activity and modulate WBC and platelet adhesive interactions and angiogenesis.