Endocrine Regulation of Oogenesis in the Medaka, Oryzias latipes
Regulation of ovarian activity is an integrated process encompassing both extraovarian signals and intrafollicular factors. The medaka, Oryzias latipes, has served as an excellent experimental model for studying the regulation of various processes of oogenesis such as oocyte growth, maturation, and ovulation. The advantage of the medaka model is the precise daily ovarian cyclicity and the ease of isolating large numbers of oocytes for in vitro studies. In addition, because of the identification of maturation-inducing hormones (steroids) in fish oocytes, the endocrine regulation of oocyte maturation has been investigated most extensively in fishes, including medaka. Here we provide a brief overview of the gene regulation of hormonally controlled processes of oocyte growth, maturation, and ovulation mainly in medaka, and present some novel data on the steroidogenic shift occurring in ovarian follicles during oocyte growth and maturation.
KeywordsLuteinizing Hormone Granulosa Cell Oocyte Maturation Ovarian Follicle Germinal Vesicle
Qurt strain medaka was provided by National BioResource Project Medaka (NBRP Medaka) of Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. This work was supported in part by Grants-in-Aid for Scientific Research on Priority Areas from the Ministry of Education, Science and Culture of Japan and the SORST Research Project of Japan Science, and Technology Corporation.
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