Metabolism of arachidonic acid in leukocytes: isolation of a 5,15-dihydroxy-eicosatetraenoic acid.

A novel metabolite of arachidonic acid was isolated from incubations of peripheral blood leukocytes with the fatty acid and the ionophore A23187. The compound was purified by high performance liquid chromatography and identified by ultraviolet photometry and gas chromatography-mass spectrometry as a 5,15-dihydroxy-6,8,11,13-eicosatetraenoic acid. The compound was also isolated from incubations of human leukocytes with the 15S-hydroperoxy-5,8,11,13(Z,Z,Z,E)-eicosatetraenoic acid, suggesting a double dioxygenation mechanism in the formation of this new metabolite of arachidonic acid. A 5S,15S-dihydroxy-6,8,11,13(E,Z,Z,E)-eicosatetraenoic acid was obtained from incubations of 5S-hydroxy-6,8,11,14(E,Z,Z,Z)-eicosatetraenoic acid with the soybean lipoxygenase and reduction with stannous chloride, and was used as reference compound.