Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
J Pharmacol Exp Ther. 2001 Apr;297(1):103-13.

Comparison of the modulatory effects of human and rat liver microsomal metabolism on the estrogenicity of bisphenol A: implications for extrapolation to humans.

Author information

  • 1Department of Pharmacology and Therapeutics, University of Liverpool, New Medical Building, Ashton St., Liverpool, L69 3BX UK.

Abstract

Bisphenol A [BPA, 2,2-bis(4-hydroxyphenyl)propane], a xenoestrogen, is a monomer for the synthesis of polycarbonate plastics, epoxy resins, and composites. Metabolism of BPA to the monoglucuronide will determine the extent of its estrogenicity in vivo. Investigation of the metabolism of BPA (500 microM) by isolated female rat hepatocytes confirmed the formation of BPA glucuronide as the major metabolite. There was a significant difference (p < 0.05) between the V(max) (mean +/- S.E.M., n = 4) of glucuronidation by pooled male or female human (four livers in each case) and immature female rat liver microsomes (5.9 +/- 0.4, 5.2 +/- 0.3, and 31.6 +/- 8.1 nmol/min/mg of protein, respectively). Estrogenic activity of BPA, assessed in a coupled microsomal metabolism-yeast estrogenicity assay, was decreased 3- and 7-fold following glucuronidation by human female and immature female rat liver microsomes, respectively. Incubations of BPA with pooled human or rat liver microsomes, in the presence of NADPH, resulted in the formation of 5-hydroxybisphenol A [2-(4,5-dihydroxyphenyl)-2-(4-hydroxyphenyl)propane], which was 10-fold less potent than BPA in the yeast estrogenicity assay. However, there was insufficient turnover to achieve a significant effect on the estrogenic activity of BPA. Because human liver microsomes did not glucuronidate BPA as extensively as the rat liver microsomes, estrogen target tissues in humans may be subject to greater exposure to BPA than the tissues of the immature female rats used for assessing estrogenicity of xenobiotics.

PMID:
11259533
[PubMed - indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Write to the Help Desk