A binary screening assay for pro-oestrogens in food: metabolic activation using hepatic microsomes and detection with oestrogen sensitive recombinant yeast cells.
Food Addit Contam
; 19(12): 1138-47, 2002 Dec.
Article
en En
| MEDLINE
| ID: mdl-12623674
ABSTRACT
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.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Contaminación de Alimentos
/
Congéneres del Estradiol
/
Análisis de los Alimentos
Tipo de estudio:
Diagnostic_studies
/
Evaluation_studies
/
Risk_factors_studies
/
Screening_studies
Límite:
Animals
/
Humans
Idioma:
En
Revista:
Food Addit Contam
Asunto de la revista:
CIENCIAS DA NUTRICAO
Año:
2002
Tipo del documento:
Article
País de afiliación:
Reino Unido