title: GnRH and its receptor (GnRH-R) are expressed in the canine placenta and uterus.
abstract: In reproductive tissues, GnRH participates in the regulation of cell growth and proliferation by direct binding to the GnRH-R, which is essential for embryo implantation. However, there is no study on the expression and cellular localization of GnRH and GnRH-R in the canine uterus and placenta. Therefore, bitches were ovariohysterectomized 10 to 12 days after mating (vaginal cytology and progesterone measurement), the uteri were flushed, and if embryos were detectable, bitches were allocated to the embryo positive group (E-pos.; preimplantation, n = 5). Other bitches were operated at later stages and, dependent on the gestational age, either allotted to the post-implantation group (Day 18-25 after mating, n = 9), or the mid-gestation group (Day 30-40 after mating, n = 3). Dogs negative in embryo flushing served as controls (E-neg.; controls, n = 5). Samples of the entire uterine wall were taken from the middle of the horn in E-neg. and E-pos. groups, and from placental and interplacental uterine sites in post-implantation and mid-gestation groups. GnRH-R expression was localized at the mRNA and protein levels by immunohistochemistry and in situ hybridization. The expression of GnRH and GnRH-R mRNA was assessed by semiquantitative polymerase chain reaction. Additionally, both GnRH and GnRH-R mRNA were expressed in all tissues examined until mid-gestation. Relative expression of GnRH was higher than that of GnRH-R (P < 0.05). During the post-implantation stage, GnRH-R expression was significantly higher in uteroplacental than in interplacental tissues. In the uterus, GnRH-R stained strongly in the surface and glandular epithelial cells, and seemed to be weaker in myometrium and stroma. Placental signals were predominantly localized in fetal trophoblast cells and to a lesser extent in maternal decidual cells. These findings suggest a local regulatory function of GnRH during early canine pregnancy.
authors: Platform for Artificial Insemination and Embryo Transfer, Department for Small Animals and Horses, Vetmeduni Vienna, Vienna, Austria. Electronic address: Sabine.Schaefer@vetmeduni.ac.at.
authors: S
authors: S
authors: Schäfer-Somi
authors: Institute of Veterinary Anatomy, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
authors: M P
authors: MP
authors: Kowalewski
authors: Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, University of Ankara, Ankara, Turkey.
authors: H
authors: H
authors: Kanca
authors: Department of Pathology, Faculty of Veterinary Medicine, University of Afyon Kocatepe, Afyonkarahisar, Turkey.
authors: M F
authors: MF
authors: Bozkurt
authors: Institute of Veterinary Anatomy, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
authors: A
authors: A
authors: Gram
authors: VetCORE - Facility for Research, Vetmeduni Vienna, Vienna, Austria.
authors: S
authors: S
authors: Sabitzer
authors: Department of Obstetrics and Gynaecology, Faculty of Veterinary Medicine, University of Dicle, Diyarbakir, Turkey.
authors: I
authors: I
authors: Kucukaslan
authors: Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, University of Ondokuz Mayıs, Samsun, Turkey.
authors: S S
authors: SS
authors: Ay
authors: Department of Obstetrics and Gynecology, Veterinary Faculty, Near East University, Nicosia, TRNC.
authors: S
authors: S
authors: Aslan
mesh_terms: D000818:Animals; D004285:Dogs / Q000502:physiology*; D005260:Female; D005786:Gene Expression Regulation; D007987:Gonadotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism*; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D060888:Real-Time Polymerase Chain Reaction; D011966:Receptors, LHRH / Q000235:genetics / Q000378:metabolism*; D014599:Uterus / Q000378:metabolism*
chemical_list: D011966:Receptors, LHRH; D007987:Gonadotropin-Releasing Hormone
keywords: Domestic dog (Canis familiaris); GnRH; GnRH-receptor; Placenta; Uterus