Effect of alkylphenols on adult male medaka: plasma vitellogenin goes up to the level of estrous female

The effect that oral administration of four alkylphenols, (1) bisphenol A (BPA), (2) p-t-octylphenol (OP), (3) p-nonylphenol (NP) and (4) p-n -nonylphenol (n- NP), as well as 17alpha-ethynylestradiol (EE2) had on male medaka fish vitellogenin was investigated. The male medaka was fed diets containing different concentrations of these chemicals for 7 days, after which their plasma vitellogenin levels were measured. Vitellogenin levels up to approximate to 10(7) ng/ml were found. This value is close to that of the normal estrous female medaka. The median effective concentration (EC50) values resulting from BPA, OP, NP and EE2 in the diet were calculated as 1600, 2600 940 and 0.37 mug/g diet, respectively. (C) 2003 Elsevier B.V. All rights reserved.