Ovulation in medaka: Endocrine regulation and the relation with the event of oocyte maturation

2015 Fiscal Year Final Research Report

• Project/Area Number: 24247010
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Morphology/Structure
• Research Institution: Hokkaido University
• Principal Investigator: Takahashi Takayuki 北海道大学, 理学(系)研究科(研究院), 特任教授 (80197152)
• Co-Investigator(Kenkyū-buntansha): OGIWARA KATSUEKI 北海道大学, 大学院理学研究院, 助教 (00422006)
• Project Period (FY): 2012-05-31 – 2016-03-31
• Keywords: 排卵 / メダカ / 内分泌制御

Outline of Final Research Achievements

Using in vitro ovulation system established for medaka ovarian follicles, we investigated the mechanism by which ovulation-related genes/proteins, membrane type-2 matrix metalloproteinase (MT2-MMP) and prostaglandin E2 receptor subtype (EP4b) were induced at ovulation. Expression of both genes/proteins was under the control of LH. Our data indicated that LH induced the expression of a transcription factor nuclear progestin receptor (nPR) in the granulosa cells and that nPR, together with other transcription factors, played roles in the subsequent expression of MT2-MMP and EP4b. We next examined if a communication between granulosa cells and the oocyte in the follicles may be important for successful ovulation. Preovulatory follicles were treated with carbenoxolone, a gap-junction inhibitor, using in vitro ovulation system. We found strong inhibition of MT2-MMP expression by the treatment, indicating that ovulation would be influence by oocyte maturation event occurring in the oocyte.

Free Research Field

生殖生物学