Inhibition of prostaglandin biosynthesis by eicosapentaenoic acid.
Eicosapentaenoic acid [20 : 5 (n-3)] is not oxidized by the purified cyclooxygenase from sheep vesicular glands in the conditions of low peroxide tone in which arachidonate [20 : 4 (n-6)] is rapidly oxygenated. When the level of peroxide in incubation mixtures is allowed to rise, there is a dramatic change in reactivity of the cyclooxygenase to react with 20 : 5 (n-3) at one-halt the rate and one-third the extent observed with 20 : 4 (n-6). Overall, the low peroxide levels expected in vivo would most probably cause the (n-3) type of fatty acid to be a general inhibitor of prostaglandin formation, through both reversible and irreversible actions at the enzyme site.
D000818:Animals; D004537:Eicosanoic Acids / Q000494:pharmacology*; D015118:Eicosapentaenoic Acid; D005231:Fatty Acids, Unsaturated / Q000378:metabolism / Q000494:pharmacology*; D011448:Prostaglandin Antagonists / Q000494:pharmacology; D011449:Prostaglandin Endoperoxides / Q000096:biosynthesis*; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D011463:Prostaglandins H / Q000096:biosynthesis*; D012756:Sheep
D004537:Eicosanoic Acids; D005231:Fatty Acids, Unsaturated; D011448:Prostaglandin Antagonists; D011449:Prostaglandin Endoperoxides; D011463:Prostaglandins H; D015118:Eicosapentaenoic Acid; D011451:Prostaglandin-Endoperoxide Synthases