title: Production of prostaglandin F2 alpha and E2 in explants of intrauterine tissues of guinea pigs during late pregnancy and labor.
abstract: Prostaglandin production in amnion and decidua is considered important for human parturition. We investigated in pregnant guinea pigs, a species similar to women in regard to the endocrinology of pregnancy, whether the production rates of PGE2 and PGF2 alpha in various intrauterine tissues are compatible with a role in parturition. Net production rates were measured at 45, 55 and 65 days of gestation and during labor in amnion, chorion, myo-endometrium, the outer layer of the myometrium, the site of placental implantation, and placenta. Net production rates in amnion increased between 45 days and labor (30-fold for PGE2 and 8-fold for PGF2 alpha, P < 0.0001). During labor, the production rates in amnion of PGE2 (P = 0.006) and PGF2 alpha (P = 0.019) were higher than at 45, 55, and 65 days of gestation. In myo-endometrium, the production rates of PGF2 alpha were higher at 65 days of gestation than at 55 days and during labor (P = 0.046). Addition of arachidonic acid (10(-5) M) increased production of PGE2 and/or PGF2 alpha in all tissues (P < 0.05) except placenta. In amnion, the response to arachidonic acid increased with advancing gestation. This suggests that 1) PGE2 and PGF2 alpha produced by amnion have a potential role in the initiation and maintenance of labor, 2) PGF2 alpha produced by myo-endometrium has a potential role in the initiation of labor, 3) cyclooxygenase(s) are not rate-limiting except in placenta, and 4) the expression of cyclooxygenase in amnion increases with advancing gestation.
authors.affiliation: Department of Obstetrics and Gynaecology, University of Auckland, New Zealand.
authors.forename: J C
authors.initials: JC
authors.lastname: Schellenberg
authors.forename: W
authors.initials: W
authors.lastname: Kirkby
mesh_terms: D000650:Amnion / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology; D015237:Dinoprost / Q000096:biosynthesis*; D015232:Dinoprostone / Q000096:biosynthesis*; D004717:Endometrium / Q000033:anatomy & histology / Q000378:metabolism; D005260:Female; D005865:Gestational Age; D006168:Guinea Pigs; D007743:Labor, Obstetric / Q000378:metabolism*; D009215:Myometrium / Q000378:metabolism; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D014599:Uterus / Q000378:metabolism*
chemical_list: D016718:Arachidonic Acid; D015237:Dinoprost; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone