12S,20-dihydroxyicosatetraenoic acid: a new icosanoid synthesized by neutrophils from 12S-hydroxyicosatetraenoic acid produced by thrombin- or collagen-stimulated platelets.

A new metabolite of arachidonic acid, formed during interaction between thrombin- or collagen-stimulated platelets and unstimulated neutrophils, has been demonstrated by both thin-layer radiochromatography and high-performance liquid chromatography. Production of the 3H-labeled metabolite in combined suspensions containing [3H]arachidonate-labeled platelets and unlabeled neutrophils from aspirin-treated donors suggested that platelet 3H-labeled 12S-hydroxy-5,8-cis,10-trans,14-cis-icosatetraenoic acid (12-HETE) was the precursor. This was confirmed by identification of the same product when purified 12-[3H]HETE was added directly to unstimulated neutrophils. Hydrogenation and oxidation of the isolated product, followed by gas chromatography-mass spectrometry showed the structure to be 12S,20-dihydroxyicosatetraenoic acid. These experiments further show that platelet stimuli known to occur in vivo may initiate metabolic interactions between different cell types via the arachidonic acid pathway.