Butyl paraben and propyl paraben modulate bisphenol A and estradiol concentrations in female and male mice

People are routinely exposed to the antimicrobial preservatives butyl paraben (BP) and propyl paraben (PP), as well as the monomer of polycarbonate plastics, bisphenol A (BPA). These chemicals are reliably detected in human urine and potentially interact. We investigated whether BP or PP exposure can modulate the concentrations of C-14-BPA and 17 beta-estradiol (E-2). Female and male CF1 mice were each given a subcutaneous injection of oil containing 0 (vehicle), 1, 3, or 9 mg BP or PP, then given a dietary supplement containing 50 mu g/kg 14C-BPA. Radioactivity was measured in tissues through liquid scintillation counting. Significantly elevated C-14-BPA concentrations were observed following BP treatment in blood serum of both sexes, as well as the lungs, uterus, and ovaries of females and the testes and epididymides of males. Treatment with PP significantly elevated C-14-BPA concentrations in the uterus only. In another experiment, female and male CF1 mice were each injected with vehicle, 3 mg BP, or 3 mg PP, and E-2 was measured in urine 2-12 h later. Whereas PP did not affect E-2, BP significantly elevated E-2 6-10 h after injection in females and 8 h after injection in males. These data indicate that BP and PP can alter the pharmacokinetics of BPA in vivo, and that BP can modulate E-2 concentrations. These results are consistent with evidence that parabens inhibit enzymes that are critical for BPA and E2 metabolism, and demonstrate the importance of considering concurrent exposure to multiple chemicals when determining regulatory exposure limits. (C) 2017 Elsevier Inc. All rights reserved.