CYTOCHROME-P450 METABOLITES OF ARACHIDONIC-ACID IN HUMAN PLACENTA

Little is known about the epoxygenase pathway of the arachidonic acid cascade in uterine tissues. In this paper, we describe the forma tion of epoxyeicosatrienoic acids (EETs) and dihydroxyeicosatrienoic acids (DHETs) in human term placenta after uncomplicated pregnancies. Metabo lism of [H-3]-arachidonic acid was analyzed in short term tissue cultu res of placenta by reverse phase HPLC. Major metabolites coeluted with authentic EETs and DHETs. The formation of EETs was inhibited by carb on monoxide. In non-radioactive incubations with biopsies from seven d ifferent placentas, sufficient material for GC/MS analysis was obtaine d. The combined media were purified by solid phase extraction and reve rse phase HPLC. The fraction coeluting with DHETs was derivatized with pentafluorobenzylbromide (PFB) and bis(trimethylsilyl)-trifluoroacety lacetamide (BSTFA) and analyzed by GC/NICI/MS/MS. 11,12-DHET and 14,15 -DHET were identified by their mass spectra displaying specific fragme nts at m/z 149 and m/z 189, respectively. Our results suggest that the epoxygenase pathway is active in human term placenta.