Metabolism of prostaglandin E2 on the fetal and maternal sides of intact fetal membranes

Abstract

The metabolism of prostaglandin E2 (PGE2) added to the chorio-decidual side or the amnion side of the intact fetal membrane was compared. Similar rates of metabolism were found when the PGE2 was added to the fetal side or the maternal side of the membrane, even though the amnion (on the fetal side of the membrane) contains no metabolizing enzymes. The appearance of PGE2 metabolites on the opposing side of the membrane was also independent of whether the PGE2 was added to the fetal or maternal side, which suggests that the chorion, which lies between the amnion and the decidua, is the major determinant of the rate of metabolism of PGE2. Furthermore, it might be expected that less PGE2 metabolism subsequent to diffusion across the membrane may occur on the amnion side, since this tissue contains no metabolizing enzymes, but no evidence for this was found. PGE2 synthesized by the amnion would therefore have little effect on PGE2 levels on the maternal side of the fetal membrane, and may not be directly involved in labour.