Bisphenol A induces transforming growth factor-β3 mRNA in the preoptic area: A cDNA expression array and Northern blot study

To gain better understanding of the effects of bisphenol A (BPA) in the adult brain, a cDNA expression array was used to screen possible candidates for BPA-inducible genes in the medial preoptic area (MPOA). Adult ovariectomized rats were given a subcutaneous injection of 10 mg BPA or sesame oil alone as a control. Twenty-four hours after the injection, the MPOAs were dissected and total RNAs were extracted. When expression levels of cDNAs derived from pooled samples were compared to controls, the expression levels of some genes in BPA-injected rats appeared to be different from those in sesame oil-injected rats. Among the candidate genes, we focused on an increase in the expression of transforming growth factor (TGF)-β3 mRNA. To quantify the change in TGF-β3 mRNA by BPA, we examined the effects of 10 mg BPA (n = 6), 1 μg 17β-estradiol (n = 6), or oil injection (n = 6) on the expression of TGF-β3 mRNA in the MPOA of ovariectomized rats by Northern blot. The TGF-β3 mRNA level in the MPOA of BPA-injected rats was significantly increased compared to the level in oil-injected rats (p < 0.05). Injection of 1 μg 17β-estradiol did not have any significant effect. The results suggest that, in the adult female rat, BPA acts on the MPOA by altering the expression of the TGF-β3 gene in a manner distinct from that of estrogen.