Researcher Information

OGIWARA Katsueki

Associate Professor

Studies on ovarian function in vertebrates.

Department of Biological Sciences, Reproductive and Developmental Biology


Studies on the molecular mechanisms of oogenesis, maturation, ovualtion, and tissue repair after ovulation by using molecular biological, endocrinological, and biochemical approaches.

FieldReproductive biology, Biochemistry, Molecular biology, Endocrinology
KeywordMouse, Medaka, Ovary, Ovulation, Follicle, Follicle selection, Hormone, Protease

Introduction of Research

We are interested in vertebrate reproduction, especially ovarian function. We are focusing on unknown issues of ovarian function and studying on molecular mechanisms of oogenesis, maturation, ovulation, and tissue repair after ovulation.
Ovary has many follicles and an oocyte grows in the follicle. Follicle consists of an oocyte surrounded by a single or multiple layers of follicular cells which support growth and maturation of the oocyte. The mature fertiliable oocytes are released from ovary into ovarian cavity (ovulation), and the follicular layers remained in the ovary are degraded and removed from the ovary at different speed (depending on species) (Figure 1). Many issues are remained to be studied in the processes. We are studying the issues using mouse and medaka fish. We have studied medaka ovulation mechanism using in vitro culture system. When isolated follicles or whole ovary are cultured in the medium, they can be ovulated in vitro (Figure 2 and 3). We have identified the enzymes (ovulation enzymes) responsible for follicle rupture during ovulation using the system and the molecular mechanism of medaka ovulation has been clarified. The study allows us to challenge to study the unknown issues that are difficult to elucidate because ovulation enzymes have not been identified. We are studying to elucidate the issues and are also challenging to study the molecular mechanism of mouse ovulation and follicle selection (Figure 4). For details of our research topics, please see at our website.


Representative Achievements

Gelatinase A and membrane-type matrix metalloproteinases 1 and 2 are responsible for follicle rupture during ovulation in the medaka, K. Ogiwara, N. Takano, M. Shinohara, M. Murakami, T. Takahashi, Proc Natl Acad Sci USA, 2005, 102, 8442-8447.
Specificity of the medaka enteropeptidase serine protease and its usefulness as a biotechnological tool for fusion-protein cleavage, K. Ogiwara, T. Takahashi, Proc Natl Acad Sci USA, 2007, 104, 7021-7026.
Apparent involvement of plasmin in early-stage follicle rupture during ovulation in medak, K. Ogiwara, K. Minagawa, N. Takano, T. Kageyama, T. Takahashi, Biol. Reprod. 2012, 86(4) 113, 1-10.
The role of urokinase plasminogen activator and plasminogen activator inhibitor-1 in follicle rupture during ovulation in the teleost medaka, K. Ogiwara, A. Hagiwara, S. RajapakseT. Takahashi, Biol. Reprod. 2015, 92(1), 10.
A Dual Role for Melatonin in Medaka Ovulation: Ensuring Prostaglandin Synthesis and Actin Cytoskeleton Rearrangement in Follicular Cells, K. Ogiwara, T. Takahashi, Biol. Reprod. 2015, 94(3) ,64.
Affiliated academic societyZoological Science of Japan, The Japan Society for Comparative Endocrinology
Room addressFaculty of Science Building No.5 5-1106