Drinking Water with Uranium below the U.S. EPA Water Standard Causes Estrogen Receptor–Dependent Responses in Female Mice Stefanie Raymond-Whish,1 Loretta P. Mayer,1 Tamara O'Neal,1 Alisyn Martinez,1 Marilee A. Sellers,1 Patricia J. Christian,2 Samuel L. Marion,2 Carlyle Begay,2 Catherine R. Propper,1 Patricia B. Hoyer,2 and Cheryl A. Dyer1 1Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA; 2Department of Physiology, College of Medicine, University of Arizona, Tucson, Arizona, USA Abstract Background: The deleterious impact of uranium on human health has been linked to its radioactive and heavy metal–chemical properties. Decades of research has defined the causal relationship between uranium mining/milling and onset of kidney and respiratory diseases 25 years later. Objective: We investigated the hypothesis that uranium, similar to other heavy metals such as cadmium, acts like estrogen. Methods: In several experiments, we exposed intact, ovariectomized, or pregnant mice to depleted uranium in drinking water [ranging from 0.5 µg/L (0.001 µM) to28 mg/L (120 µM) . Results: Mice that drank uranium-containing water exhibited estrogenic responses including selective reduction of primary follicles, increased uterine weight, greater uterine luminal epithelial cell height, accelerated vaginal opening, and persistent presence of cornified vaginal cells. Coincident treatment with the antiestrogen ICI 182,780 blocked these responses to uranium or the synthetic estrogen diethylstilbestrol. In addition, mouse dams that drank uranium-containing water delivered grossly normal pups, but they had significantly fewer primordial follicles than pups whose dams drank control tap water. Conclusions: Because of the decades of uranium mining/milling in the Colorado plateau in the Four Corners region of the American Southwest, the uranium concentration and the route of exposure used in these studies are environmentally relevant. Our data support the conclusion that uranium is an endocrine-disrupting chemical and populations exposed to environmental uranium should be followed for increased risk of fertility problems and reproductive cancers. Key words: depleted uranium, endocrine disruption, estrogen, estrogen receptor, female reproduction, heavy metal, Navajo reservation. Environ Health Perspect 115:1711–1716 (2007) . doi:10.1289/ehp.9910 available via http://dx.doi.org/ [Online 14 September 2007] Address correspondence to C.A. Dyer, Northern Arizona University, Department of Biological Sciences, P.O. Box 5640, Building 21, Room 227, South Beaver St., Flagstaff, AZ 86011 USA. Telephone: (928) 523-6294. Fax: (928) 523-7741. E-mail: Cheryl.Dyer@nau.edu We thank R. Audet, J. Getz, H. Miers, T. Layton, and Z. Robinson for their technical assistance. This work was supported by National Institutes of Health grants R15 ES013481, IMSD GM 056931, U54 CA096320, and F31 CA110210 (SRW) and an American Physiological Society Porter Predoctoral Fellowship (S.R.W.) . The authors declare they have no competing financial interests. Received 20 November 2006 ; accepted 13 September 2007. The full version of this article is available for free in HTML or PDF formats. |