Mechanisms of parturition: the transfer of prostaglandin E2 and 5-hydroxyeicosatetraenoic acid across fetal membranes.
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.
Bennett
P R
PR
Department of Obstetrics and Gynaecology, St. George's Hospital Medical School, London, England.
Chamberlain
G V
GV
Patel
L
L
Elder
M G
MG
Myatt
L
L
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
D006893:Hydroxyeicosatetraenoic Acids; D013395:Sucrose; D015232:Dinoprostone