Uterine expression of prostaglandin H2 synthase in late pregnancy and during parturition in prostaglandin F receptor-deficient mice.
PG production in uterine tissues is important for many physiological processes in late pregnancy, including parturition. We examined the expression of the PGH2 synthases, cyclooxygenase-1 (COX-1) and COX-2, in uterine tissues during late pregnancy, using PGF receptor-deficient (FP-/-) mice. Female FP-/- mice are unable to deliver normal fetuses at term, as they do not undergo luteolysis necessary for parturition. In wild-type mice, COX-1 messenger RNA (mRNA) was expressed in the endometrial epithelium, myometrium, and decidua throughout late pregnancy. The expression of COX-1 mRNA in the endometrial epithelium and myometrium decreased both in wild-type mice undergoing natural parturition and in FP-/- mice undergoing ovariectomy-induced parturition, but expression of COX-1 mRNA was enhanced in FP-/- mice at the expected term. In wild-type mice, COX-2 mRNA was not expressed in the myometrium before parturition, but was markedly induced during parturition. This induction of COX-2 was absent in FP-/- mice at the expected term, but was found during ovariectomy-induced parturition in these mice. Expression of COX-2 proteins was confirmed by immunohistochemical analysis. Thus, in uterine tissues, myometrial expression of COX-2 is closely associated with the occurrence of parturition, but uterine expression of COX-1 is induced much earlier and kept at a high level until parturition occurs. These results suggest that COX-1-derived PGs are responsible for the induction of luteolysis, and that COX-2-derived PGs play a role in the final pathway of parturition.
Tsuboi
K
K
Department of Physiological Chemistry, Faculty of Pharmaceutical Sciences, Kyoto University, Japan.
Sugimoto
Y
Y
Iwane
A
A
Yamamoto
K
K
Yamamoto
S
S
Ichikawa
A
A
D000818:Animals; D015152:Blotting, Northern; D003338:Corpus Luteum / Q000502:physiology; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D004958:Estradiol / Q000097:blood; D005260:Female; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007527:Isoenzymes / Q000096:biosynthesis; D007743:Labor, Obstetric / Q000378:metabolism*; D008565:Membrane Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009215:Myometrium / Q000166:cytology / Q000201:enzymology; D010052:Ovariectomy; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D011374:Progesterone / Q000097:blood; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D011982:Receptors, Prostaglandin / Q000172:deficiency* / Q000235:genetics; D014599:Uterus / Q000166:cytology / Q000201:enzymology*
D007527:Isoenzymes; D008565:Membrane Proteins; D011982:Receptors, Prostaglandin; C034671:prostaglandin F2alpha receptor; D011374:Progesterone; D004958:Estradiol; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; C496512:Ptgs1 protein, mouse