RESUMO
BACKGROUND: Phytoestrogens are a diverse group of non-steroidal compounds that occur naturally in many plants. Because they possess a ring system similar to estrogens they are able to bind to estrogen receptors in humans. In the present study we tested the effects of the phytoestrogens genistein and daidzein on the production of human chorionic gondaotropin (hCG) in isolated trophoblast cells of term placentas in vitro. METHODS: Genistein and daidzein were incubated at different concentrations with trophoblast cells. Untreated cells were used as controls. At designated times aliquots were removed and tested for hCG production. RESULTS: Production of the protein hormone hCG was influenced by the phytoestrogens genistein and daidzein in trophoblast cells. We found a significant decrease of hCG production in genistein- and daidzein-treated trophoblast cells that was concentration-dependent. Compared with daidzein, genistein seems to be a more efficient inhibitor of the production of hCG. CONCLUSION: The phytoestrogens genistein and daidzein can reduce hCG production in human term trophoblasts. Both phytoestrogens belong to the group of isoflavones, which are enriched in soy-containing foods and are widely consumed by humans for putative beneficial health effects. Because both phytoestrogens have inhibitory effects on hCG production during pregnancy, exposure to these estrogen-like compounds during sensitive periods of development may have the capacity to alter the function of the reproductive system and thereby influence fertility.