PARENT SESSION
IP06 - The Japanese Medaka Model
8:00 AM to 12:00 PM - Monday, 18 November 2002
Room Room 151 G

(IP39) Effects of environmental chemicals on the early life stage and reproduction of Japanese medaka (Oryzias latipes).

Ishibashi, Hiroshi^*,1, Matsumura, Naomi², Hirano, Masashi², Nishihara, Tsutomu³, Arizono, Koji², ¹ Graduate School of Science and Technology, Nagasaki University, Nagasaki, Japan² Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Kumamoto, Japan³ Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan

ABSTRACT- Various environmental chemicals are known to affect the development and function of endocrine systems in wildlife and humans, and are shown to have estrogenic activity in vitro and in vivo, which may disrupt reproductive function in fish. In this study, we investigated effects of pesticides and fungicides as compared with estrogenic compounds (estradiol-17beta, genistein, nonylphenol and bisphenol-A) on the early life stage, reproduction (e.g., the egg number and fertility of paired medaka), hepatic vitellogenin and cytochrome P450s using Japanese medaka (Oryzias latipes). In addition, polymerization-initiators, which were widely used in dental composite resin, were also tested estrogenic abilities using this system. On the other hand, we determined the estrogenic activity of those compounds using by the yeast two-hybrid assay in vitro.

Key words: Oryzias latipes, environmental chemical, reproduction, yeast two-hybrid assay