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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 THE FEMALE LONG EVANS HOODED RAT
Citation:
RYAN, B., 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 THE FEMALE LONG EVANS HOODED RAT. Presented at Triangle Consortium for Reproductive Biology, Chapel Hill, NC, February 11, 2006.
Description:
Anthropogenic estrogens are pervasive in the environment. The effects of these 'xenoestrogens' are controversial in humans, although there is a clear indication that some fish species are adversely affected in contaminated ecosystems. The current project focuses on the effects of developmental exposure in rats 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; however, exposure to estrogens during development can also alter sexual differentiation of the nervous system and behavior of female rats. For this reason, we chose to study both sexually dimorphic reproductive (lordosis response) and sexually dimorphic non-reproductive behaviors (saccharin preference and motor activity) and reproductive tract morphology in female rats. Pregnant dams were exposed to EE (0.05, 0.5, 5 and 50g/kg/day) or BPA (2, 20 and 200g/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 EE dose groups (5 and 50g/kg/day) displayed 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 contrast to EE, developmental exposure to BPA caused no consistent effects in any of the endpoints measured to date. The findings show behavioral disruption in the rat by EE at perinatal doses lower than previously published. This project was funded by the EPA/NCSU Cooperative Research Grant CT826512010 and the EPA/UNC Cooperative Research Grant T 829472. This abstract does not necessarily reflect EPA policies.