Document Detail


A binary screening assay for pro-oestrogens in food: metabolic activation using hepatic microsomes and detection with oestrogen sensitive recombinant yeast cells.
MedLine Citation:
PMID:  12623674     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
An assay, employing microsomes prepared from rat liver and a recombinant cell bioassay (RCBA) expressing the human oestrogen receptor (alpha) linked to a reporter gene, was evaluated for the detection of pro-oestrogens in food using methoxychlor and mestranol as model compounds. Bio-activation of the hop phytoestrogen isoxanthohumol to the potent oestrogen 8-prenylnaringenin was also investigated. The oestrogenic potency values for reference standards determined with the RCBA (17beta-oestradiol = 100%) were: methoxychlor 0.0025%, mestranol 1.3%, isoxanthohumol 0.001%, and for their potential respective metabolites were: bishydroxymethoxychlor 0.015%, 17alpha-ethynyl oestradiol 69% and 8-prenylnaringenin 0.4%. Incubation of methoxychlor and mestranol (10 microM) with microsomes prepared from the liver of rats treated with Aroclor 1254 significantly increased (p < 0.001) their oestrogenic potency from 0.0021 and 2.4% to 0.015 and 8.3%, respectively. In contrast, the potency of the hop phytoestrogen isoxanthohumol was unchanged. Metabolites were identified by UV-HPLC-MS/MS as monohydroxy methoxychlor and HPTE from methoxychlor, and the major metabolite of mestranol was 17alpha-ethynyl oestradiol. There was no evidence for the metabolism of isoxanthohumol. Mestranol was also activated by microsomes induced with saline (control), beta-napthoflavone, 3-methylcholantherene, isoniazid or pregnenolone-16alpha-carbonitrile, but not phenobarbitone. These studies demonstrate the principle for use of a binary assay system for the detection of pro-oestrogens and indicate the potential value for risk assessment of endocrine disrupting chemicals.
Authors:
N G Coldham; R Horton; M F Byford; M J Sauer
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Publication Detail:
Type:  Evaluation Studies; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Food additives and contaminants     Volume:  19     ISSN:  0265-203X     ISO Abbreviation:  Food Addit Contam     Publication Date:  2002 Dec 
Date Detail:
Created Date:  2003-03-07     Completed Date:  2003-03-26     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8500474     Medline TA:  Food Addit Contam     Country:  England    
Other Details:
Languages:  eng     Pagination:  1138-47     Citation Subset:  IM    
Affiliation:
Department of Risk Research, Veterinary Laboratories Agency, Addlestone, Surrey KT15 3NB, UK. n.g.coldham@vla.defra.gsi.gov.uk
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MeSH Terms
Descriptor/Qualifier:
Animals
Biological Assay / methods
Biotransformation
Chromatography, High Pressure Liquid / methods
Estradiol Congeners / analysis*,  pharmacokinetics
Estrogen Receptor alpha
Food Analysis / methods*
Food Contamination / analysis*
Genes, Reporter
Humans
Insecticides / analysis
Mestranol / analysis
Methoxychlor / analysis
Microsomes, Liver / metabolism
Rats
Receptors, Estrogen / genetics
Yeasts / drug effects
Chemical
Reg. No./Substance:
0/Estradiol Congeners; 0/Estrogen Receptor alpha; 0/Insecticides; 0/Receptors, Estrogen; 72-33-3/Mestranol; 72-43-5/Methoxychlor

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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