Thromboxane A3 (TXA3) is formed in human platelets after dietary eicosapentaenoic acid (C20:5 omega 3).

Platelet-rich plasma of subjects, who had ingested cod liver oil containing 10% eicosapentaenoic acid (C20:5 omega 3), the precursor of trienoic prostanoids, was stimulated ex vivo with collagen. Formation of thromboxane B3, the hydrolysis product of non-aggregatory thromboxane A3, from endogenous eicosapentaenoic acid was demonstrated by combined capillary gas chromatography-mass spectrometry. Concomitantly platelet aggregation in platelet-rich plasma upon low doses of collagen and associated thromboxane B2 formation from endogenous arachidonic acid were reduced. We conclude that both the formation of inactive thromboxane A3 as well as the reduction of thromboxane A2 may contribute to the reduced platelet reactivity after dietary eicosapentaenoic acid.