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Types of Effects Found in Animals at Low Doses

Female Reproductive Tract: Studies have noted abnormalities in the female reproductive tract from low dose neonatal exposure, including
abnormalities in the ovaries and reproductive tracts of aged female mice and early vaginal opening. In utero exposure in rats to low levels of BPA has been found to promote uterine disruption in rat offspring and to alter vaginal morphology of post-pubertal offspring.

Male Reproductive System: BPA has been associated with rat reproductive system changes, reduced daily sperm production,reduced mice testis weight, and enhanced anogenital distance.

Early Puberty: Several studies report early onset of sexual maturation in female mice occurring at low maternal doses.

Meiotic Failure: Mice exposed to low BPA doses had high rates of meiotic failure, specifically an increase in aneuploid eggs and embryos.

Reduced Sperm Count: Low-dose developmental or adult exposure reduced daily sperm production and fertility in males in rat and mouse studies.

Mammary Gland Development: Low-dose BPA exposure stimulated mammary gland development in mice in several studies. Fetal BPA exposure was reported to induce the development of pre-neoplastic and neoplastic lesions in the mammary gland.

Prostate disease and cancer: Low-dose maternal, and fetal exposure to BPA increased prostate size in male mouse offspring. Neonatal exposure to low doses of BPA increased susceptibility to precancerous prostatic lesions in rats as they aged and sensitized the prostate gland to adult-induced hormonal carcinogenesis. Low dose BPA exposure for a few days after birth predisposed male rats to develop prostate cancer in adulthood.

Diabetes and Obesity: Low-level chronic exposure to BPA induced insulin resistance in adult mice. Insulin resistance is associated with type 2 diabetes, hypertension and cardiovascular disease. Low-dose BPA produced insulin resistance in male mice. Continuous exposure of mice to BPA before and shortly after birth caused the development of obesity and hyperlipidemia. Scientists at the National Institute of Environmental Health Sciences (NIEHS) concluded that brief exposure early in life to environmental endocrine-disrupting chemicals, especially those with estrogenic activity like BPA, can increase body weight as mice age.

Impaired Immune Function: Several studies show altered immune function occurring in mice at low BPA doses.

Behavioral Changes: Behavioral effects noted in animals following low BPA exposure include hyperactivity; increased aggression; changes in response to painful or fear-provoking stimuli;elimination of sex differences in behavior; changes in maternal behavior (e.g., reductions in time spent nursing, increases in time resting away from offspring, and increases in time spent out of the nest); and altered socio-sexual behaviors.

Brain Effects: BPA has been shown to inhibit the activity of estrogen in the rat brain, which normally increases the growth and regulates the viability of connections between neurons, impairing learning and memory among rats. In several studies, low-dose exposure to BPA caused changes in the reproductive system and social behaviors.

What are the most vulnerable times for exposures to Bisphenol A (BPA) and the Phthalate DEHP? During pregnancy and for children up to young adulthood. Protecting the fetus and children from exposures is very important. See pages 21-28 and pages 40-44 for the heath effects of Bisphenol A (BPA) and the phthalate DEHP in Environment and Human Health, Inc.'s report, "Plastics That May be Harmful to Children and Reproductive Health."

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