title: Evidence for a PGF2α auto-amplification system in the endometrium in mares.
abstract: In mares, prostaglandin F2α (PGF2α) secreted from the endometrium is a major luteolysin. Some domestic animals have an auto-amplification system in which PGF2α can stimulate its own production. Here, we investigated whether this is also the case in mares. In an in vivo study, mares at the mid-luteal phase (days 6-8 of estrous cycle) were injected i.m. with cloprostenol (250 µg) and blood samples were collected at fixed intervals until 72 h after treatment. Progesterone (P4) concentrations started decreasing 45 min after the injection and continued to decrease up to 24 h (P < 0.05). In turn, 13,14-dihydro-15-keto-PGF2α (PGFM) metabolite started to increase 4h after an injection and continued to increase up to 72 h (P < 0.05). PGF receptor (PTGFR) mRNA expression in the endometrium was significantly higher in the late luteal phase than in the early and regressed luteal phases (P < 0.05). In vitro, PGF2α significantly stimulated (P < 0.05) PGF2α production by endometrial tissues and endometrial epithelial and stromal cells and significantly increased (P < 0.05) the mRNA expression of prostaglandin-endoperoxide synthase-2 (PTGS2), an enzyme involved in PGF2α synthesis in endometrial cell. These findings strongly suggest the existence of an endometrial PGF2α auto-amplification system in mares.
authors.affiliation: Laboratory of Reproductive PhysiologyGraduate School of Environmental and Life Science, Okayama University, Okayama, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kozai
authors.affiliation: Laboratory of Reproductive PhysiologyGraduate School of Environmental and Life Science, Okayama University, Okayama, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Tokuyama
authors.affiliation: Laboratory of Reproductive PhysiologyGraduate School of Environmental and Life Science, Okayama University, Okayama, Japan Department of Reproductive ImmunologyInstitute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Poland.
authors.forename: Anna Z
authors.initials: AZ
authors.lastname: Szóstek
authors.affiliation: Shadai CorporationHokkaido, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Toishi
authors.affiliation: Shadai CorporationHokkaido, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Tsunoda
authors.affiliation: Shadai CorporationHokkaido, Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Taya
authors.affiliation: Kyushu Okinawa Agricultural Research CenterNational Agriculture and Food Research Organization (NARO), Kumamoto, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Sakatani
authors.affiliation: Kyushu Okinawa Agricultural Research CenterNational Agriculture and Food Research Organization (NARO), Kumamoto, Japan Department of Animal ScienceHokkaido University, Hokkaido, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: Equine Science DivisionHidaka Training and Research Center, Japan Racing Association, Hokkaido, Japan Obihiro University of Agriculture and Veterinary MedicineObihiro, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Nambo
authors.affiliation: Department of Reproductive ImmunologyInstitute of Animal Reproduction and Food Research, Polish Academy of Sciences, Olsztyn, Poland.
authors.forename: Dariusz J
authors.initials: DJ
authors.lastname: Skarzynski
authors.affiliation: Laboratory of Reproductive PhysiologyGraduate School of Environmental and Life Science, Okayama University, Okayama, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Yamamoto
authors.affiliation: Laboratory of Reproductive PhysiologyGraduate School of Environmental and Life Science, Okayama University, Okayama, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Kimura
authors.affiliation: Laboratory of Reproductive PhysiologyGraduate School of Environmental and Life Science, Okayama University, Okayama, Japan Obihiro University of Agriculture and Veterinary MedicineObihiro, Japan kokuda@okayama-u.ac.jp.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Okuda
mesh_terms: D000020:Abortifacient Agents, Nonsteroidal / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D003338:Corpus Luteum / Q000187:drug effects / Q000378:metabolism*; D015237:Dinoprost / Q000031:analogs & derivatives / Q000097:blood / Q000494:pharmacology*; D004717:Endometrium / Q000187:drug effects / Q000378:metabolism*; D030762:Estrous Cycle / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D006736:Horses; D011374:Progesterone / Q000097:blood; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017154:Stromal Cells / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000020:Abortifacient Agents, Nonsteroidal; D012333:RNA, Messenger; C008228:15-keto-13,14-dihydroprostaglandin F2alpha; D011374:Progesterone; D015237:Dinoprost