Transformation of arachidonic acid in leukocytes. isolation and structural analysis of a novel dihydroxy derivative

Abstract

A suspension of mixed peripheral blood leukocytes was incubated with arachidonic acid. After ether extraction and silicic acid fractionation of the products, the fraction containing the mono- and dihydroxy derivatives of arachidonic acid was further analyzed by high pressure liquid chromatography on silica gel and octadecyl silica (reversed-phase) columns. A previously undescribed metabolite was detected and isolated in pure form. The compound co-chromatographed with leukotriene B 4 on octadecyl silica but was eluted earlier than leukotriene B 4 from silica gel columns. Ultraviolet spectrophotometry, gas chromatography-mass spectrometry, ozonolysis and steric analysis indicated that the new metabolite was the 5S,12S-dihydroxy-6,8,10,14-icosatetraenoic acid. The yield of the novel dihydroxy acid was 1 to 4% of the added substrate. The new metabolite showed less than 1% of the myotropic activity of leukotriene B4 on the guinea pig lung parenchymal strip.