title: Oxytocin receptor is differentially expressed in mouse endometrium and embryo during blastocyst implantation.
abstract: The oxytocin (OT)-oxytocin receptor (OTR) system of the mammalian uterus has mainly been studied in relation to its involvement in the onset of labor. The aim of this study was to elucidate the in vivo expression and localization pattern of OTR in the mouse endometrium and embryo during implantation, as well as OTR mRNA expression in the in vitro developing mouse embryo. The expression of OTR or OT was detected immunohistochemically in uterine tissue sections of 5- to 8-week-old female mice between days 4 and 10 of an established pregnancy. In addition, the expression of OTR mRNA was detected by means of reverse transcription polymerase chain reaction (RT-PCR) in mouse oocytes and embryos up to the blastocyst stage. The mean ratios of normalized expression levels of OTR gene in all samples were also calculated. The recorded increase in OTR mRNA immediately after fertilization could mean a possible role of OT in this process, as OTR mRNA gradually decreased after the four-cell stage of pre-embryonic development. The differential expression of OTR during embryonic apposition and embryonic invasion/placentation in the mouse uterus suggests a potential role of OT in the implantation process of the mouse. It is possible that the interaction of OTR with the hormones included in the ovulation induction regiments utilized today in in vitro fertilization (IVF) could be affecting the receptivity/quality of the implanting endometrium.
authors.affiliation: First Department of Obstetrics and Gynecology, Division of Reproductive Medicine, Athens University Medical School, 50 Achaias St., 115 23, Athens, Greece. pberet@biol.uoa.gr
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Beretsos
authors.forename: Dimitris
authors.initials: D
authors.lastname: Loutradis
authors.forename: Stauros
authors.initials: S
authors.lastname: Koussoulakos
authors.forename: Loukas H
authors.initials: LH
authors.lastname: Margaritis
authors.forename: Erasmia
authors.initials: E
authors.lastname: Kiapekou
authors.forename: George
authors.initials: G
authors.lastname: Mastorakos
authors.forename: Irini
authors.initials: I
authors.lastname: Papaspirou
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Makris
authors.forename: Antonis
authors.initials: A
authors.lastname: Makrigiannakis
authors.forename: Aris
authors.initials: A
authors.lastname: Antsaklis
mesh_terms: D000818:Animals; D010064:Embryo Implantation; D004622:Embryo, Mammalian / Q000378:metabolism*; D004717:Endometrium / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D051379:Mice; D011247:Pregnancy; D012333:RNA, Messenger / Q000032:analysis; D018045:Receptors, Oxytocin / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D012333:RNA, Messenger; D018045:Receptors, Oxytocin