Human exposure to endocrine disrupters: Standardisation of a marker of estrogenic exposure in adipose tissue

In many epidemiological studies based on the direct measurement of exposure to organochlorines, the chemicals of concern are determined directly from adipose tissue samples. Although the measurement of all possible organochlo rines, their metabolites, isomers and congeners may be desirable, it is exp ensive and time-consuming and many chemicals with hormonal activity may not yet have been identified. Testing systems are therefore required to screen for estrogenicity and to identify appropriate biomarkers of human exposure . To address this issue, we developed and standardised a method to assess t he total estrogenic xenobiotic burden in human adipose tissue. The method e xtracts and separates the more lipophilic xenoestrogens from ovarian estrog ens, with a subsequent bioassay determination of the cumulative effect of t he xenoestrogens. It was applied to 400 women, using 200 mg of adipose tiss ue: 65% of samples showed measurable estrogenicity in the fraction where mo st non-polar xenoestrogens eluted, and 76% of fractions where ovarian estro gens eluted were positive for estrogenicity. Residues of 16 organochlorine pesticides were determined. No correlation was found between pesticide cont ent and estrogenicity of the samples. The high percentage of positive sampl es suggests that the method is sensitive enough to be used as a biomarker o f human exposure to estrogenic xenobiotics and can be applied in epidemiolo gical studies.