Effects of environmental and natural estrogens on vitellogenin production in hepatocytes of the brown frog (Rana temporaria).

The objective of this study was to investigate the ability of the natural estrogens and synthetic estrogens as well as the estrogen mimics to induce estrogen-receptor mediated vitellogenesis in primary hepatocytes of the brown frog (Rana temporaria). Based on EC50 values the following order was determined for the potency of the estrogens: 17beta-estradiol (EC50: 19-43 nM) approximately ethynylestradiol (EC50: 13-80 nM)>estrone (EC50: 218-241 nM)>DES (EC50: 338-3537 nM). Exposure to bisphenol A and methoxychlor concentrations up to 100 microM did not have any effect on in vitro vitellogenesis.