EICOSANOID PRODUCTION BY INTRAUTERINE TISSUES BEFORE AND AFTER LABOR IN SHORT-TERM TISSUE-CULTURE

Prostanoid production by intrauterine tissues from pregnant and non-pr egnant women has been studied intensively over the last decade. Little is known about the lipoxygenase metabolites of arachidonic acid (AA). The production of prostaglandins and HETEs by pregnancy specific huma n tissues was investigated in a short-term culture system. Tissue samp les were obtained after uncomplicated pregnancies from placenta, fetal membranes and decidua of deliveries before (n=6) and after the onset of labor (n=8) and incubated for 1 hour in oxygenated HBSS. In the sup ernatant, PGE2, PGF2alpha, 6-keto-PGF1alpha and TXB2 were measured wit h RIA and 15-, 12- and 5-HETE with HPLC and UV-detection. The main AA- metabolite in all tissue incubations was 12-HETE. Decidua produced 12 to 28 times more prostaglandins than placenta and fetal membranes with 6-keto-PGF1alpha as the main metabolite. The main cyclooxygenase deri vative measured from placenta and fetal membrane incubations was TXB2. After labor, fetal membranes showed an increase in total prostaglandi n (significant for PGE2) and a decrease in HETE synthesis. The physiol ogic significance of 12-HETE in reproduction is still poorly understoo d, but a shift in AA metabolism from HETEs to prostaglandins may be in volved in the initiation of labor. Furthermore, these results point to different roles of the tissue compartments within the pregnant uterus for the parturition process.