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AN ASSESSMENT OF THE EFFECTS OF GESTATIONAL AND LACTATIONAL EXPOSURE TO ETHINYL ESTRADIOL (EE) AND BISPHENOL A (BPA) ON REPRODUCTIVE MORPHOLOGY AND BEHAVIOR IN FEMALE AND MALE LONG EVANS HOODED RAT
Citation:
RYAN, B., K. HOWDESHELL, J. G. VANDENBERGH, K. M. CROFTON, AND L. E. GRAY. AN ASSESSMENT OF THE EFFECTS OF GESTATIONAL AND LACTATIONAL EXPOSURE TO ETHINYL ESTRADIOL (EE) AND BISPHENOL A (BPA) ON REPRODUCTIVE MORPHOLOGY AND BEHAVIOR IN FEMALE AND MALE LONG EVANS HOODED RAT. Presented at Society of Toxicology, San Diego, CA, March 05 - 09, 2006.
Description:
Anthropogenic estrogens are pervasive in the environment. Although the effects of these 'xenoestrogens' are controversial in humans, some fish species are adversely affected in contaminated ecosystems. The current project focuses on the effects of developmental exposure to two estrogenic compounds: EE, the principle estrogen in many oral contraceptives and BPA, a component of polycarbonate plastic. Studies investigating endocrine disruptors typically focus on reproductive endpoints. Exposure to estrogens during development can alter sexual differentiation of the nervous system and behavior of female rats as well as the male and female reproductive tract. For this reason, we chose to study both sexually dimorphic reproductive (lordosis response) and sexually dimorphic non-reproductive behaviors (saccharin preference and motor activity) in female rats and reproductive tract morphology in both male and female rats. Pregnant dams were exposed to EE (0.05, 0.5, 5 and 50 g/kg/day) or BPA (2, 20 and 200 g/kg/day) from gestational day 7 to postnatal day 18. EE treatment at the highest dose caused some pup mortality. Females in the two highest dose groups (5 and 50 g/kg/day) displayed an early vaginal opening and malformations of the external genitalia. These doses of EE also masculinized lordosis behavior and saccharin preference in female offspring and disrupted reproductive tract development in both sexes. In contrast to EE, developmental exposure to BPA caused no consistent effects in any of the endpoints measured to date. The findings show behavioral disruption by EE at doses lower than previously published. This project was funded by the EPA/NCSU Cooperative Research Grant CT826512010. This abstract does not necessarily reflect EPA policies.