US EPA

733390 

Journal Article 

Abstract 

Effects of environmental endocrine disruptors on sexual differentiation of the brain and behavior 

Aou, S 

2004 

Yes 

Congenital Anomalies
ISSN: 0914-3505
EISSN: 1741-4520 

44 

4 

A21 

The effects of exposure to endocrine disruptors during the fetal and suckling periods on the sexual differentiation of behaviors and the brain were examined. We administered bisphenol A (BPA; 0.1, 1, and 5 mg/L) and diethylstilbestrol (DES; 50 ug/L) to mother rats via the drinking water during pregnancy and lactation. In the control group, female offspring were more active in the open field test, and had a larger locus coeruleus than males. BPA exposure abolished sex differences regarding open- field behavior and inverted the volume of the locus coeruleus without any remarkable change in the reproductive system. The rats exposed to DES did not show any sexual dimorphism in the open field test. A reversal of the sex difference in the locus coeruleus volume was also observed, as in the BPA-treated animals. In contrast to BPA, DES inhibited the female reproductive function and reduced the body weight of male offspring. These results suggest that BPA and DES disrupt the sexual differentiation of the brain and non-reproductive behavior in a similar manner, but that of the reproductive function and body weight control in different ways. The locus coeruleus, the major source of noradrenergic neurons, is highly sensitive to low-dose administration of BPAand DES. Noradrenaline has been shown to modulate not only many different kinds of behaviors, but also different types of neuronal responses to sensory, visceral and motor stimuli including reward-related neuronal responses in the lateral hypothalamic area, the amygdala, and the orbitofrontal cortex. Impairments of sexual differentiation of the locus coeruleus may affect these diverse brain functions. 

Japanese Teratology Society 44th Annual Meeting 

July 15-17, 2004