FORMATION AND METABOLISM OF 14,15-EPOXYEICOSATRIENOIC ACID BY HUMAN REPRODUCTIVE TISSUES

Human granulosa-luteal cells cultured in the presence of arachidonic acid produced low levels of the epoxygenase metabolite 14,15-epoxy-5,8,11-(Z,ZZ)-eicosatrienoic acid (14,15-EpETrE) as determined by HPLC analysis and gas chromatography mass spectrometry. When authentic 14,15-[H-3]EpETrE was incubated with these cells in the absence of serum it was metabolised initially to the dihydroxy derivative (14,15-dihydroxy-5,8,11-eicosatrienoic acid, 14,15-DiHETrE) and subsequently to a number of more polar metabolites as determined by HPLC. Fetal calf serum protected 14,15-EpETrE from metabolism for at least 2 h. A similar pattern of metabolism was obtained when 14,15-[H-3]EpETrE was incubated with a human choriocarcinoma cell line (BeWo). Microsomes from this cell line converted arachidonic acid to a large number of radioactive metabolites including 14, 15-DiHETrE and 11,12-DiHETrE although there was no evidence for the parent epoxides. These results extend earlier findings that human reproductive tissues produce epoxygenase metabolites, and demonstrate the rapid metabolism of these compounds by intact cells in the absence of serum.