A deregulated expression of estrogen-target genes is associated with an altered response to estradiol in aged rats perinatally exposed to bisphenol A.

Here we assessed the effects of perinatal exposure to bisphenol A (BPA) on the uterine response to 17β-estradiol (E2) in aged rats. Pregnant rats were orally exposed to 0.5 or 50 μg BPA/kg/day from gestational day 9 until weaning. On postnatal day (PND) 360, the rats were ovariectomized and treated with E2 for three months. The uterine tissue of BPA50 and BPA0.5 rats showed increased density of glands with squamous metaplasia (GSM) and glands with daughter glands respectively. Wnt7a expression was lower in GSM of BPA50 rats than in controls. The expression of estrogen receptor 1 (ESR1) and its 5'- untranslated exons ESR1-O and ESR1-OT was lower in BPA50 rats. Both doses of BPA modified the expression of coactivator proteins and epigenetic regulatory enzymes. Thus, perinatal BPA-exposed rats showed different glandular abnormalities associated with deregulated expression of E2-target genes. Different mechanisms would be involved depending on the BPA dose administered.