IP03 Avian Endocrine Test Protocols
B113 & B114
1:20 PM - 4:40 PM, Monday
(IP019) Sex Reversal Test Using a New Quail Model, F1(AWE x WE), is Useful to Assess Estrogenic Endocrine Activity as Tier 1 in vivo Screening.
Shibuya, K.1, Satou, K.1, Mazutani, M.1, Wada, M.2, Shimada, K. 3, Nunoya, T. 1, 1 Nippon Institute for Biological Science, Tokyo, Japan2 Tokyo Medical and Dental University, Chiba, Japan3 Nagoya University, Nagoya, Japan
ABSTRACT- Tier 1 screening battery in birds for assessment of endocrine disrupting effects of chemicals has not been completed. There are a few candidates of in vitro and in vivo screening method such as estrogen receptor binding assay, mRNA detection of vetellogenin (Vg) and very low density lipoprotein, and monitering of blood Vg level. We have developed a new in vivo screening method for evaluating estrogenic endocrine activity of chemicals using Japanese quail embryo. F1(AWE x WE) Japanese quail has been produced by mating between male AWE (albino plumage color) and female WE (wild plumage color) strains. The male and female F1 quail exhibit exactly wild and albino phenotypes, respectively, ruled by a criss-cross inheritance. Therefore, it is easy to determine genetic sex in the embryo stage. Using fertile eggs of F1(AWE x WE), 17 beta-estradiol (E2), ethynylestradiol (EE), diethylstilbestrol (DES), nonylphenol (NP), and bisphenol A (BPA) were assessed. Twenty micro-L of corn oil containing various doses of the test substances were injected in egg white just before the incubation. Control eggs received the same volume of corn oil alone. At 16 days of incubation, embryos were grossly observed and the gonad was processed to histological preparations. The incidence and degree of ovotestis were examined histopathologically as endpoints. Exposure of E2, EE and DES resulted in a dose-dependent increase in incidence and degree of ovotestis. Both NP and BPA also induced ovotestis with significantly higher incidences compared with the controls, whereas the incidence and degree were not dependent on dose levels. This in vivo screening method using F1(AWE x WE) is inexpensive, simple and can reduce time to achieve results, so that the screening method is a promising candidate to evaluate feminization effects of estrogenic endocrine disrupters in birds (The present study was partly supported by Ministry of the Environment, Japan).
Key words: Japanese quail, in vivo screening, F1(AWE x WE), ovotestis