title: Canine prostaglandin E2 synthase (PGES) and its receptors (EP2 and EP4): expression in the corpus luteum during dioestrus.
abstract: In the dog CL are the only source of the progesterone in cyclic and pregnant animals. From a high expression of cyclooxygenase 2 (Cox2) at the beginning of the dioestrus and a low one at the end it was suggested that prostanoids may play a role in the formation of the CL. This led to the hypothesis that also in the dog PGE2 of luteal origin might act as paracrine/autocrine factor. Hence, expression of the prostaglandin E2 synthase (PGES) and its receptors (EP2 and EP4) was determined during the course of dioestrus in canine CL from days 5, 15, 25, 35, 45, 65 after ovulation, following cloning of PGES using SMART RACE PCR, which revealed a high homology (82-94%) with other species. Real Time (TaqMan) PCR showed a high PGES and EP2 expression in the early CL-phase with a significant decrease thereafter. EP4 revealed a constant expression pattern throughout the life span of the CL. In situ hybridization co-localized PGES, EP2 and EP4 in the cytoplasm of the luteal cells only. In conclusion, our data suggest that in the dog PGE2 of luteal origin acts by autocrine mechanism as a luteotropic factor through its EP2 and EP4 receptors during the phase of CL-formation.
authors.affiliation: Clinic for Obstetrics, Gynecology and Andrology of Large and Small Animals, Justus-Liebig-University Giessen, Giessen, Germany. kowalewskipl@yahoo.de
authors.forename: Mariusz Pawel
authors.initials: MP
authors.lastname: Kowalewski
authors.forename: Henry M'ikiugu
authors.initials: HM
authors.lastname: Mutembei
authors.forename: Bernd
authors.initials: B
authors.lastname: Hoffmann
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003338:Corpus Luteum / Q000201:enzymology / Q000502:physiology*; D017931:DNA Primers; D018076:DNA, Complementary / Q000235:genetics; D004031:Diestrus / Q000502:physiology*; D004285:Dogs; D005260:Female; D005784:Gene Amplification; D015870:Gene Expression; D019746:Intramolecular Oxidoreductases / Q000235:genetics*; D008969:Molecular Sequence Data; D010060:Ovulation / Q000502:physiology; D000071876:Prostaglandin-E Synthases; D018078:Receptors, Prostaglandin E / Q000235:genetics*; D058307:Receptors, Prostaglandin E, EP2 Subtype; D058309:Receptors, Prostaglandin E, EP4 Subtype; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D018078:Receptors, Prostaglandin E; D058307:Receptors, Prostaglandin E, EP2 Subtype; D058309:Receptors, Prostaglandin E, EP4 Subtype; D019746:Intramolecular Oxidoreductases; D000071876:Prostaglandin-E Synthases