Sex-specific influence of maternal exposure to bisphenol A on sodium and fluid balance in response to dipsogenic challenges in rats

The plasticizer bisphenol A (BPA) is one of the highest volume chemicals produced worldwide. Human exposure to BPA occurs almost constantly. BPA is an endocrine disruptor that interferes in estrogen receptor functions. This is important for the developing brain, which is particularly sensitive to the estrogenic effects of BPA. Body fluid balance is maintained by a complex network of systems that regulate sodium and water intakes and electrolyte excretion. The development of these control systems occurs during early life and therefore, may be susceptible to changes in the uterine environment. The aim of this work was to study the effects of two low BPA doses in the dam, during pregnancy and lactation, on adult offspring drinking and sodium and urine excretion after dipsogenic challenge. Dams were exposed to BPA in drinking water to mimic the most likely route of human exposure. The results showed that BPA did not disrupt spontaneous fluid balance, but altered sodium and fluid intakes in the BPA offspring under osmotic challenges. In experiments, both 24h fluid deprivation and sodium depletion modified fluid ingestive response in BPA offspring compared to control offspring. The increased preference for 2.7% NaCl solution in male BPA offspring is similar to female control offspring, altered ingestive behavior appears to be due to feminization of males and "hyperfeminization" of female BPA offspring, as they drink more than female control offspring. Our results indicate that exposure to low doses of BPA in early life may disrupt the development of sex-specific drinking behaviors by altering the steroid programming of the brain, and this disruption affects males and females differently.