The roles of the cyclo-oxygenases types one and two in prostaglandin synthesis in human fetal membranes at term

The aim of this study was to determine the relative contributions of cyclo- oxygenase (COX) types 1 and 2 to prostaglandin synthesis at term. Methods: Fetal membranes were collected from 6 pregnancies after elective c aesarean section at term, prior to labour. The presence of COX-1 and COX-2 protein was determined using Western analysis. The relative contributions o f the two isoforms of COX to prostaglandin synthesis were determined by inc ubation of fetal membrane discs with either a COX-2 selective inhibitor, SC 236, or a COX-I selective inhibitor, SC560, and measurement of prostaglandi n release during 24 h using enzyme-linked immuno-sorbent assay (ELISA). Results: Both COX-I and COX-2 protein were demonstrated in amnion and chori on-decidua. The COX-2 selective inhibitor, SC-236, significantly reduced pr ostaglandin synthesis, both in its COX-2 specific and higher, non-specific concentration ranges. The COX-1 selective inhibitor, SC-560, had no effect upon prostaglandin synthesis in its COX-I specific concentration range, but did significantly reduce prostaglandin synthesis at higher, non-selective concentrations. Conclusions: Fetal membranes contain both COX-1 and COX-2 at term, but only COX-2 contributes towards prostaglandin synthesis. COX-2 selective NSAI dr ugs will be as effective as non-selective agents in inhibition of fetal mem brane prostaglandin synthesis and may represent a new strategy for tocolysi s. (C) 2000 Harcourt Publishers Ltd.