Science Inventory

In utero and lactational exposure to bisphenol A, in contrast to ethinyl estradiol, does not alter sexually dimorphic behavior, puberty, fertility, and anatomy of female LE rats.

Citation:

RYAN, B. C., A. K. Hotchkiss, K. M. CROFTON, AND L. E. GRAY. In utero and lactational exposure to bisphenol A, in contrast to ethinyl estradiol, does not alter sexually dimorphic behavior, puberty, fertility, and anatomy of female LE rats. TOXICOLOGICAL SCIENCES. Society of Toxicology, RESTON, VA, 114(1):1-4, (2010).

Impact/Purpose:

The current study was designed to determine if maternal exposure to relatively low oral doses of EE2 or BPA in utero and during lactation' would alter the expression of well characterized sexually dimorphic behaviors or alter the age of puberty or reproductive function in the female LE rat offspring.

Description:

Many chemicals released into the environment display estrogenic activity including the oral contraceptive ethinyl estradiol (EE2) and the plastic monomer bisphenol A (BPA). EE2 is present in some aquatic systems at concentrations sufficient to alter reproductive function of fishes. Many concerns have been raised about the potential effects of BPA. The National Toxicology Program rated the potential effects of low doses of BPA on behavior and CNS as an area of "some concern", whereas most effects were rated as of "negligible" or "minimal" concern. However, the number of robust studies in this area was limited. The current study was designed to determine if maternal exposure to relatively low oral doses of EE2 or BPA in utero and during lactation' would alter the expression of well characterized sexually dimorphic behaviors or alter the age ofpuberty or reproductive function in the female LE rat offspring. Pregnant rats were gavaged with vehicle, EE2 (0.05 to 50 ug/kg/day) or BPA (2, 20 and 200 ug/kg/day) from day 7 of gestation to postnatal day 18 and the female offspring were studied. EE2 (50 ug/kg/day) increased anogenital distance and reduced pup body weight at PND2, accelerated the age at vaginal opening, reduced F1 fertility and F2 litter sizes and induced malformations of the external genitalia (5 ug/kg), Fl females exposed to EE2 also displayed a reduced (male-like) saccharin preference (5 ug/kgj.and absence of lordosis behavior (15 ug/kg), indications of defeminization of the CNS. BPA had no effect on any of the aforementioned measures. These results demonstrate that developmental exposure to pharmacologically-relevant dosage levels of EE2 can permanently disrupt the reproductive morphology and function of the female rat.

URLs/Downloads:

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Record Details:

Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Product Published Date: 03/01/2010
Record Last Revised: 06/23/2010
OMB Category: Other
Record ID: 214577

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LABORATORY

TOXICOLOGY ASSESSMENT DIVISION

REPRODUCTIVE TOXICOLOGY BRANCH