title: Mechanisms of parturition: the transfer of prostaglandin E2 and 5-hydroxyeicosatetraenoic acid across fetal membranes.
abstract: Prostaglandin E2 production by amnion is thought to be an important event in the onset of human labor. It has been suggested that 5-hydroxyeicosatetraenoic acid, also produced in the amnion, may mediate prelabor contractions. For either of these compounds to play a paracrine role they need to cross the chorion, which has a high capacity to metabolize prostaglandins. With the use of an in vitro system we have shown that both prostaglandin E2 and 5-hydroxyeicosatetraenoic acid cross either amnion or intact amnion-chorion-decidua at a rate similar to that of an extracellular marker sucrose. Analysis by high performance liquid chromatography revealed that at physiologic concentrations neither prostaglandin E2 nor 5-hydroxyeicosatetraenoic acid were metabolized by amnion alone. Moreover, 100% of the 5-hydroxyeicosatetraenoic acid and 72% of the prostaglandin E2 remained in the active form after passage across intact amnion-chorion-decidua. There did not appear to be any difference in the rate of transfer or permeability of the membranes before or after spontaneous labor. We conclude that both 5-hydroxyeicosatetraenoic acid and prostaglandin E2 synthesised in the amnion can cross the membranes by diffusion through the extracellular space, remaining largely unmetabolized, and may play a role in the onset of human labor.
authors.affiliation: Department of Obstetrics and Gynaecology, St. George's Hospital Medical School, London, England.
authors.forename: P R
authors.initials: PR
authors.lastname: Bennett
authors.forename: G V
authors.initials: GV
authors.lastname: Chamberlain
authors.forename: L
authors.initials: L
authors.lastname: Patel
authors.forename: M G
authors.initials: MG
authors.lastname: Elder
authors.forename: L
authors.initials: L
authors.lastname: Myatt
mesh_terms: D001692:Biological Transport; D001696:Biomechanical Phenomena; D002851:Chromatography, High Pressure Liquid; D003656:Decidua / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism*; D005321:Extraembryonic Membranes / Q000378:metabolism*; D005260:Female; D006801:Humans; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism*; D007743:Labor, Obstetric / Q000502:physiology*; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D013395:Sucrose / Q000378:metabolism
chemical_list: D006893:Hydroxyeicosatetraenoic Acids; D013395:Sucrose; D015232:Dinoprostone