WP8 Environmental Neuromodulation
Room 19A/B, Level 4
2:10 PM - 5:30 PM, Wednesday, 12 November 2003
Chair: Brooks, Bryan ,
Co-chair: Huggett, Duane ,
(466) Estrogenic Endocrine Disrupting Chemicals Impair Reproductive Neuroendocrine and Behavioral Responses in Japanese Quail.
Ottinger, M1, Hazelton, J1, Wu, J1, Ruscio, M1, Thompson, N1, Quinn, M, Abdelnabi, M, Beavers, J2, Jaber, M2, 1 Department of Animal and Avian Sciences, University of Maryland, College Park, Maryland, USA2 Wildlife International, Ltd., Easton, Maryland, USA
ABSTRACT- Endocrine disrupting chemicals (EDCs) include pesticides, herbicides, and other chemicals that impact endocrine systems by mimicking or interfering with steroid hormones. Positive control experiments were conducted in which quail embryos were exposed to estradiol (E2) or testosterone (T) over a range of ages. Results showed that exposure to E2 or T by embryonic day 12 (17 day incubation) demasculinized male sexual behavior in Japanese quail and resulted in long term alterations in hypothalamic neurotransmitters, including norepinephrine, dopamine, and serotonin. Further, E2 treatment reduced egg production ( p ≤ 0.5; 90.2 vs 54.1; control vs E2) and fertility (85.3 vs 33.4%, control vs E2). Embryonic exposure to methoxychlor (MXC) also impaired male sexual behavior in adult quail. Subsequent studies have been conducted in which Japanese quail were exposed to dietary MXC (0, 0.5, 5, or 10ppm) in a 2 generation paradigm, beginning as adults (P1), continuing in their offspring (F1), with observation of their offspring (F2), raised on control diet. MXC exposure impaired male sexual behavior, hypothalamic catecholamines, and plasma steroid hormones. Sexual maturation appeared to be delayed in both males and females. Moreover, MXC exposure had reproductive consequences at every level of MXC used in this study. This suggests that embryonic steroid exposure interferes with sexual differentiation of neural systems that direct reproductive endocrine and behavioral responses in adults. Supported by EPA #R826134010 (Star Grant), NSF #9817024, and EPA R-2877801(MAO).
Key words: neuroendocrine systems, japanese quail, reproductive behavior, reproductive axis