摘要：

An 'in culture' bioassay was developed to assess the estrogenicity of xenobiotics using human breast estrogen-sensitive MCF7 cells. The assay compares the cell yield achieved after 6 days of culture in medium supplemented with 10% charcoal-dextran stripped human serum in the presence or absence of estradiol (10 -13 to 10 -9 M), and with diverse concentrations of xenobiotics suspected of being estrogenic. Among the chemicals tested (pesticides, phytoestrogens, polychlorobiphenyls, alkylphenols and phytohormones), the bioassay confirmed the estrogenicity of compounds previously shown to be estrogenic in rodent models; no false positives were found. In addition, a case of estrogen contamination due to the shedding of estrogenic xenobiotics by polystyrene labware was solved using this assay. This bioassay has the following advantages over those currently used: a) it is easy to perform: it requires a standard cell culture facility and a human estrogen-sensitive cell line; b) it is relevant to humans, since it relies on the responses of a human cell line growing in human serum-supplemented media, and c) it is sensitive since it detects 10pg/ml estradiol-17β. This assay may also be used to determine the presence of estrogenic xenobiotics in soil, water, human foods and animal feeds. Among the foods and feeds tested, a soy bean drink and a laboratory rat chow were shown to be estrogenic. We believe that the adoption of this bioassay by industry and regulatory agencies may provide a rigorous tool to identify estrogenic xenobiotics.

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