Bisphenol A enhances cadmium toxicity through estrogen receptor

To clarify the action of estrogenic endocrine disruptors on cadmium (Cd)-induced metallothionein (MT) synthesis in the liver, we investigated the effects of bisphenol A (BPA) on hepatic MT-1 mRNA expression and MT contents after Cd injection. Liver damáge after Cd injection was assessed by measuring glutamic-pyruvic transaminase (GPT) and glutamic-oxaloacetic transaminase (GOT) activities in the serum. It was found that BPA reduced the Cd-induced expression of MT-1 mRNA and MT protein in the liver. The administration of tamoxifen, an estrogen receptor antagonist, prevented the reduction of hepatic MT content by BPA. Moreover, both the GPT and GOT activities of the BPA-treated groups were higher than those of the control groups. These findings suggest that BPA reduced hepatic MT synthesis after Cd injection via the estrogen receptor. which resulted in increased damage to the liver.