Isoprostanes are produced by the non-enzymatic, free radical peroxidation of phospholipid-esterified arachidonic acid. They have been used as biomarkers of oxidative stress, but they also have been found to have potent biological activity. ent-8-iso-15(S)-ProstaglandinF2α (ent-8-iso-15(S)-PGF2α) is a potent vasoconstrictor of porcine retinal and brain microvessels with EC50 values of 15 and 24 nM, respectively. This isoprostane is about ten-fold more potent than 8-iso-PGF2α in a whole blood platelet aggregation inhibition assay.
8-iso-13,14-dihydro-15-keto ProstaglandinF2α (8-iso-13,14-dihydro-15-keto PGF2α) is a metabolite of the isoprostane, 8-isoprostane (8-iso PGF2α), in rabbits, monkeys and humans. 8-iso PGF2α is a PG-like product of non-specific lipid peroxidation. In both humans and monkeys, exogenously infused 8-isoprostane is converted primarily to metabolites having 2 or 4 carbon atoms removed from the top side chain by β-oxidation. A similar pattern is observed when tritiated 8-isoprostane is infused into rabbits. Early in the infusion (within 10 minutes) 8-iso-13,14-dihydro-15-keto PGF2α was a significant component of the metabolite profile, which was comprised mostly of dinor 8-isoprostane metabolites. 8-iso-13,14-dihydro-15-keto PGF2α weakly inhibits the U-46619 or collagen-induced aggregation of human platelets, although a number of the E-series isoprostanes are much more potent in this assay.
8-iso-15-keto ProstaglandinF2α (8-iso-15-keto PGF2α) is a metabolite of the isoprostane 8-iso PGF2α in rabbits, monkeys, and humans. 8-isoprostane (8-iso PGF2α) is a prostaglandin-like product of non-specific lipid peroxidation. In both humans and monkeys, exogenously infused 8-iso PGF2α is converted primarily to metabolites having 2 or 4 carbon atoms removed from the top side chain by β-oxidation. A similar pattern is observed when tritiated 8-iso PGF2α is infused into rabbits. Early in the infusion (within 1-2 minutes) 8-iso -15-keto PGF2α was a major component of the metabolite profile, which was comprised mostly of unmetabolized 8-iso PGF2α. 8-iso -15-keto PGF2α is a vasoconstrictor when tested on the rat isolated thoracic aorta, acting via the TP (thromboxane) receptor.