Disposition of bisphenol A in pregnant mice and fetuses after a single and repeated oral administration

For decades, numerous chemical pollutants have been described to interfere with endogenous hormone metabolism/signaling altering reproductive functions. Among these endocrine disrupting substances, Bisphenol A (BPA), a widely used compound, is known to negatively impact germ and somatic cells in the testis. Physical agents, such as ionizing radiation, were also described to perturb spermatogenesis. Despite the fact that we are constantly exposed to numerous environmental chemical and physical compounds, very few studies explore the impact of combined exposure to chemical and physical pollutants on reproductive health. The aim of this study was to describe the impact of fetal co-exposure to BPA and IR on testicular function in mice. We exposed pregnant mice to 10 µM BPA (corresponding to 0.5 mg/kg/day) in drinking water from 10.5 dpc until birth, and we irradiated mice with 0.2 Gy (γ-ray, RAD) at 12.5 days post-conception. Co-exposure to BPA and γ-ray induces DNA damage in fetal germ cells in an additive manner, leading to a long-lasting decrease in germ cell abundance. We also observed significant alteration of adult steroidogenesis by RAD exposure independently of the BPA exposure. This is illustrated by the downregulation of steroidogenic genes and the decrease of the number of adult Leydig cells. As a consequence, courtship behavior is modified, and male ultrasonic vocalizations associated with courtship decreased. In conclusion, this study provides evidence for the importance of broadening the concept of endocrine disruptors to include physical agents, leading to a reevaluation of risk management and regulatory decisions.

Download Full-text

124 THE REGULATION OF CALCIUM TRANSPORT GENE EXPRESSIONS DURING PREGNANCY AFTER EXPOSURE TO OCTYLPHENOL AND BISPHENOL A

Reproduction Fertility and Development ◽

10.1071/rdv25n1ab124 ◽

2013 ◽

Vol 25 (1) ◽

pp. 209

Author(s):

S. Kim ◽

E. B. Jeung

Keyword(s):

Bisphenol A ◽

Calcium Transport ◽

Corn Oil ◽

Urinary Calcium ◽

High Dose ◽

Dependent Manner ◽

Gene Expressions ◽

Protein Levels ◽

Pregnant Mice ◽

Serum And Urine

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 and kidney of the pregnant mice. From 6.5 to 16.5 days post-coitus (dpc), 5 pregnant mice for each group were orally given with ethylestradiol (EE, 0.2 mg kg–1 day –1), OP (15, 45, or 135 mg kg–1 day–1) or BPA (5 or 50 mg kg–1 day –1) dissolved in corn oil. The duodenum, kidney, blood, and urine were obtained from the mice at day 18.5 of pregnancy. As a result, serum and urinary calcium levels were decreased by OP and BPA in a dose-dependent manner. The mRNA expression levels of calcium transport genes TRPV6 and CaBP-9k were decreased in the kidney after treatment with OP and BPA, while duodenal expression of TRPV6 was reduced by a high dose of BPA. The protein levels of these genes showed similar pattern with those of mRNA in the kidney and duodenum. The data were analyzed using a one-way ANOVA. P < 0.05 was considered statistically significant. Taken together, OP and BPA altered gene expressions associated with 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.

Download Full-text