Vitamin C increases the formation of prostacyclin by aortic rings from various species and neutralizes the inhibitory effect of 15-hydroperoxy-arachidonic acid.
Aortic rings from rats, rabbits and guinea-pigs produce different amounts of 6-oxo-prostaglandin F1 alpha (6-oxo-PGF1 alpha), the stable breakdown product of prostacyclin, i.e. 2760 +/- 195, 160 +/- 10 and 87 +/- 17 pg 6-oxo-PGF1 alpha per mg wet weight in 30 min. Vitamin C enhances the production of 6-oxo-PGF1 alpha by the aortic tissue of these three species, independent of their basal release. This increase was only significant if vitamin C was present in the preincubation as well as in the incubation fluid. 15-Hydroperoxy-arachidonic acid inhibits the production of 6-oxo-PGF1 alpha (IC50:6 microM) and this inhibitory effect was completely neutralized by vitamin C. The increased production of 6-oxo-PGF1 alpha is not due to an increased release of the substrate arachidonic acid. It is suggested that vitamin C enhances the formation of 6-oxo-PGF1 alpha by protecting the cyclo-oxygenase and PGI-synthase.
D015121:6-Ketoprostaglandin F1 alpha / Q000096:biosynthesis; D000818:Animals; D001011:Aorta / Q000378:metabolism; D001095:Arachidonic Acids / Q000378:metabolism / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology*; D001808:Blood Vessels / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D011464:Epoprostenol / Q000096:biosynthesis*; D006168:Guinea Pigs; D015289:Leukotrienes; D008054:Lipid Peroxides / Q000494:pharmacology*; D008297:Male; D011817:Rabbits; D051381:Rats
D001095:Arachidonic Acids; D015289:Leukotrienes; D008054:Lipid Peroxides; D015121:6-Ketoprostaglandin F1 alpha; C025086:15-hydroperoxy-5,8,11,13-eicosatetraenoic acid; D011464:Epoprostenol; D001205:Ascorbic Acid