The metabolism of arachidonic acid (AA) and the transfer of its metabolites was determined in in vivo perfused placental tissue from normal pregnancies and those complicated by maternal insulin-dependent diabetes mellitus (IDDM). 14C-labbeled AA was recirculated in the fetal circulation for 60 min while 3H-AA was recirculated in the maternal circulation. Placental effluent was subjected to high perfomence liquid chromatography (HPLC) and analysis of dual-label scintillation counts. Placentae from IDDM pregnancies converted 3-6 times more radiolabelled AA to eicosanoids than did normal placentae. In addition, the transfer pf eicosanoids into the opposing circlulation was doubled in placentae from IDDM pregnancies compared to normal placentae. The predominant direction of eicosanoid transfer in both groups of placentae was in the fetal-to-maternal direction. The relative amoounts of eicosanoids produced was also latered in placentae from IDDM preganancies. Increased amounts of thromboxane (Tx) B2 and hydroxyeicosatetraenoic acids (HETEs) were present in both circulations of placentae from IDDM preganancies. Level of 6-keto prostaglandin F1a (6KPGF1a) were significantly reduced in both circulation in placetae from IDDM preganancies. Thus, the ratio of TxA2 to PGI2 and the ratio of HETEs to PGI2 were both significantly increased in placentae from IDDM preganancies. These results suggest an imbalance in eicosanoid production which may be relevant to abnormal placental structure and function in IDDM pregnancies.
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