RESUMO
The distribution between the aqueous and solid phase of 17 beta-estradiol in the ng-range in waste water was investigated by spiking experiments with a radio-labeled hormone. The distribution was measured by liquid scintillation counting. The major part of 17 beta-estradiol remained in the aqueous phase and did not adsorb to the solids. The fraction in the aqueous phase could be enriched by a conventional solid phase extraction with a recovery rate of up to 100%. Losses were negligible and the compound did not adsorb to the surfaces of glass bottles.
Assuntos
Estradiol/metabolismo , Eliminação de Resíduos Líquidos , Poluentes Químicos da Água/metabolismo , Adsorção , Cromatografia Líquida , Estradiol/análise , Cromatografia Gasosa-Espectrometria de Massas , Contagem de Cintilação , Sensibilidade e Especificidade , Solubilidade , Poluentes Químicos da Água/análiseRESUMO
Properties of mixtures of compounds exhibiting estrogenic potential have been questioned in the past. Synergistic effects of endocrine disrupters have been proposed, but could never be confirmed. In this study, the transactivational potential of xenoestrogens and phytoestrogens has been evaluated in a yeast test system. Pesticides such as endosulfan, dieldrin, atrazine, and the main metabolites, desethylatrazine and desisopropylatrazine, have been tested and their behavior as mixtures is compared to the behavior of the single compounds. Our results are in contrast to a report (Tran et al., 1996) on the inhibitive effects of xenoestrogens on 17 beta-estradiol-dependent transactivation. Phytoestrogens have been investigated in a similar manner. A synergistic effect could not be confirmed for both, xenoestrogens and phytoestrogens. These compounds are either weak estrogens or completely lack estrogenic potential. Their endocrine disrupting potential in more complex systems must be therefore attributed to other molecular mechanisms such as to metabolic modification or interference with steroidogenesis. This study shows that yeast systems are useful tools for monitoring pure estrogenic properties.
Assuntos
Congêneres do Estradiol/toxicidade , Estrogênios não Esteroides/toxicidade , Isoflavonas , Bioensaio , Sinergismo Farmacológico , Monitoramento Ambiental , Poluentes Ambientais/toxicidade , Estradiol/farmacologia , Humanos , Técnicas In Vitro , Praguicidas/toxicidade , Fitoestrógenos , Preparações de Plantas , Receptores de Estrogênio/efeitos dos fármacos , Receptores de Estrogênio/genética , Receptores de Estrogênio/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Ativação Transcricional/efeitos dos fármacosRESUMO
Phytoestrogens are defined as plant substances that are structurally or functionally similar to estrogen. They are present in many foods and their higher consumption in certain populations has been correlated with protection against many diseases including coronary heart disease, breast cancer and endometrial and ovarian cancer. In this report, ten phytoestrogens with diverse chemical structures were studied for their binding to the human estrogen receptor and their transcription activation properties in yeast and mammalian cells. Our results showed that some of these compounds bind with relatively high affinity to the estrogen receptor and activate the receptor in the yeast and mammalian cell system. In addition, none of these compounds showed anti-estrogenic activity. We conclude that the yeast system accurately predicts the estrogenic activity of compounds with diverse chemical structures in mammalian cells. In addition, our data with phytoestrogens that do not show transcription activation properties raise the possibility that these compounds may exert their biological effects through pathways different from the classical estrogen signalling mechanism.