Evidence for a PGF auto-amplification system in the endometrium in mares

Keisuke Kozai, Shota Tokuyama, Anna Z. Szóstek, Yuko Toishi, Nobuo Tsunoda, Kazuyoshi Taya, Miki Sakatani, Masashi Takahashi, Yasuo Nambo, Dariusz J. Skarzynski, Yuki Yamamoto, Koji Kimura, Kiyoshi Okuda

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


In mares, prostaglandin F (PGF) secreted from the endometrium is a major luteolysin. Some domestic animals have an autoamplification system in which PGF 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 ìg) 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-PGF (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, PGF significantly stimulated (P < 0.05) PGF 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 PGF synthesis in endometrial cell. These findings strongly suggest the existence of an endometrial PGF auto-amplification system in mares.

Original languageEnglish
Pages (from-to)517-526
Number of pages10
Issue number5
Publication statusPublished - May 2016

ASJC Scopus subject areas

  • Reproductive Medicine
  • Embryology
  • Endocrinology
  • Obstetrics and Gynaecology
  • Cell Biology


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