BPA modifies corticosterone secretion and brain receptors in the rat

Methods: Female Wistar rats were exposed to BPA (Sigma-Aldrich, USA) (40 microg/kg provided through corn flakes) from gestational day 1 to the end of lactation. At postnatal day 42, half of the offspring were sacrificed under basal conditions and the rest were subjected to a spatial learning task (Y-maze) prior to sacrifice. Plasma corticosterone levels were determined by Radioimmunoassay and hippocampal levels of MR and GR were assessed by Western blotting. 3-way analysis of variance (ANOVA) was used for statistical evaluation. Significance was accepted for p<0.05.

Results: BPA treatment significantly increased corticosterone levels in female offspring comparing to controls both under basal conditions (p=0.001) and following Y-maze (p=0.034). Notably, following the task, corticosterone levels increased from basal only in BPA males (p<0.0001) and control females (p=0.001). BPA treatment modified the existing sex differences on MR and GR levels under basal conditions. Following Y-maze, BPA females showed decreased MR (p=0.013) and increased GR levels (p=0.02) relative to the basal condition.

Conclusion: These data show that even a ‘safe' dose of perinatal BPA exposure can modify corticosterone signaling in the hippocampus of rats during adolescence.

This study was supported by grant by Prokter & Gamble Company