Endocrine Abstracts

Introduction: Octylphenol (OP) is a degradation product of alkylphenol ethoxylates that are widely used to in rubber, pesticides and paints. Bisphenol A (BPA) is an organic compound with two functional phenol groups and used to make polycarbonate plastic and epoxy resins, along with other applications. OP and BPA are known as endocrine disruptors that can induce inappropriate estrogenic action, and may disturb natural calcium metabolism. In the present study, the effects of OP and BPA on the calcium levels of serum and urine, and calcium transport genes were investigated in the duodenum, kidney and placenta of the pregnant mice.

Methods: From 6.5 to 16.5 days after post coitus (dpc), pregnant mice were orally given with ethylestradiol (EE, 0.2 mg/kg/day), OP (15, 45, or 135 mg/kg/day) or BPA (5 or 50 mg/kg/day) dissolved in corn oil. The duodenum, kidney, placenta, blood and urine were obtained from mice at day 18.5 of pregnancy.

Results: As a result, serum and urinary calcium levels were decreased by OP and BPA in a dose dependent manner. The expression levels of calcium transport genes, TRPV6, TRPV5 and CaBP-9k were decreased in the kidney after treatment with OP and BPA, while duodenal expression of TRPV6 was reduced by high a dose of BPA. In the placenta, the gene expressions of TRPV6 and CaBP-9k were induced in the mice treated with OP, whereas it was not altered by BPA.

Conclusion: OP and BPA altered gene expressions of calcium transport in the pregnant mice, which may cause reduced serum and urine calcium levels. These results suggest that estrogenic actions of OP and BPA may lead to influence the calcium levels during pregnancy in the mice.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.