Studies on ovarian function in vertebrates.

OGIWARA, KatsuekiAssociate Professor

Reproductive and Developmental Biology
Reproductive Biology
Studies on the molecular mechanisms of oogenesis, maturation, ovualtion, and tissue repair after ovulation by using molecular biological, endocrinological, and biochemical approaches.
Ovary and ovarian follicle
Endocrine regulation
Medaka, Oryzias latipes

One of the ovarian most significant role is to produce new ova (eggs) to pass a life into next generation. The fully grown ova, which have the ability to be fertilized, are released from the ovary. This process is called ovulation. The process known as follicle rupture has been a subject of intensive investigation over the past century. Previous studies have established that the action of proteolytic enzymes are essential for this process. Despite much effort, the whole picture about ovulation is still not clear. Recently, for the first time in vertebrates, we succeeded in identifying the enzymes that are critically involved in ovulation using medaka fish. We strongly believe this discovery as a huge step forward for our efforts to identify mechanism of ovulation in mammals. We try to identify the mammalian ovulatory enzymes using mouse as an experimental model.

As we have identified the mechanism of ovulation in the medaka, we intend to further expand our search for the regulation of expression of the hydrolytic enzymes and other factors involved in ovulation. To date, there are no available information about gene regulation during ovulation due to the lack of knowledge on ovulatory enzymes. In this study, to reveal the mechanisms for controlling the ovulation, we try to identify the regulatory proteins of the ovulatory enzyme genes. This becomes the first study of this kind in vertebrates and may elucidate a common mechanism to all vertebrates.


There are a lot of interesting topics worth studying in reproductive biology. Despite extensive investigations, still there are a lot of unanswered questions in this field. For example, in mammals, the number of oocytes ovulated at a time depends on the species. How it is decided? Many scientists have been studying about this question, but none of them have an answer. Even ovulation, which seems to be much easier to understand, has not been clearly described. Our core purpose is to understand the basic questions and to transform this knowledge to answer the problems in cloned animals, infertility treatments, artificial reproduction and overpopulation. Therefore studying reproductive biology is a strongly felt need in this era.

We welcome dynamic young people with a “can do” attitude who want to be a part of our team to explore new discoveries in this progressive field of science.


See the following web site.


Laboratory of Reproductive and Developmental Biology Ogiwara Laboratory


Faculty of Science
Department of Biological Sciences
Reproductive and Developmental Biology

Grad School

Graduate School of Life Science
Division of Life Science
Biosystems Science Course

Contact Information

Faculty of Science, Building #5 5-1106
Email: kogi [atmark] sci.hokudai.ac.jp

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