Isoprostanes are prostaglandin (PG)-like compounds produced in vivo by free radical-catalyzed peroxidation of arachidonoyl-containing lipids. 8-iso PGA2 is one of several isoprostanes produced from peroxidation of arachidonic acid esterified in phospholipids. 8-iso PGA2 is the dehydration product of 8-iso PGE2, a potent renal vasoconstrictor. Evidence for the in vivo production of 8-iso PGA2 has been shown in rat liver under conditions of oxidative stress. There are no published studies of the pharmacological properties of 8-iso PGA2.