Elevated serum vitellogenin and gonadal abnormalities in wild male founder from Tokyo Bay, Japan

We investigate the seasonal changes of serum VTG，as a biomarker of the effect of environmental估计in wild male flounder (Pleuronectes yokohamae) collected from Tokyo Bay，与这些水平相比，那些在日本的外国妇女的失败来自一个参考site along the coast of Japan.Our reference station was located off Shiriuchi in Hokkaido，where sewage and wastewater inputs to the marine environment were considered to be negligible. .Pleuronectes yokohamae from Tokyo Bayaged approximately 1 to 6yr . were caught between January 1997 and May 1998 (male: n=130, female：n=143), covering an entire reproductive season. Reference specimens collected off Shiriuchi，in the Strait of Tsugaru, between March 1997 and June 1998 (male: n= 62, female：n=64 . Mean serum levels of VTG for female flounder from Tokyo Bay and Hokkaido suggest that noobvious difference (elevated or depressed) of VTG of females was observed between the two sites. Atthe reference site off Shiriuchi, the mean VTG l…evels for male flounder was < 50ng ml -1 -1 -1 . In contrast，male flounder in Tokyo Bay showed elevated levels of VTG almost throughout the year （mean）204ng ml维D1-1维D1；ranging from < 50 ng ml d -1 d -1 to 2200 ng ml d -1 d -1 d -1 d). The VTG levels in male flounder inTokyo Bay (n=130) were significantly higher (p <0.001) compared to those of the reference fish fromHokkaido (n=62). considerable variation in serum VTG concentration observed in individual malesfrom Tokyo Bay could be due to individual differences in sensitivity to or degree of accumulation ofestrogenic compounds.The relationship VTG in male flounder from Tokyo Bay and other factorssuch as standard length, hepatosomatie index (HSI), 17β-estradiol (E - D22 - D2), testosterone (T)，and gonadosomatic index (GSI) was investigated. We found no significant relationship between VTG andstandard length which indicates that induction of VTG occurs among male flounder of all ages above一年。Furthermore，无相关性观察VTG和HSI，D22 D22 or T levels. However，high concentrations of serum VTG were observed more often in male flounder whose GSI was lower than2% in Tokyo Bay. The GSI is therefore an additional factor that should be considered when maleflounder is deployed as biomonitor of environmental estrogenes . the development of a very sensitive方法for the determination of very low levels of plasma VTG in male fish allows，a) detection of trace amounts of估计compounds and mainly，b)高diluted serum samples分析；ELISA technique, which can avoid a critical problemthe unspecific interference with serum compounds at high concentrations. We developed and optimizeda luminometric immunoassay that was able to detect trace amounts of VTG in the serum of maleflounder collected from a reference site, located off Shiriuchi in Hokkaidowhere sewage and wastewater inputs to the marine environment considered negligible.这个方法can be applied successfully to monitor seasonal changes in baseline VTG levels in serum samplesSuch results will be useful in interpreting the effects of the effectsenvironmental estrogens in ecosystems.Both E E D22 E E D2 and T in the sera of male and female fish werehigh during winter，当VTG levels in female fish and the GSI of both sexes were also high. Estrogen has been found inthe blood of wild males at level as high as 10% of those normally seen in mature females in winter。The detectable levels of VTG in The blood of wild male flounder at The reference site in winter maybe a consequence of the presence of physiologically active levels of estrogen. Perhaps this speciesexpresses VTG in both sexes in response to "natural" circulating E D22 D2.Histological analysisrevealed that the gonads of about 15% of male flounder (3 out of 20) collected off Haneda in东京Bay contained female gametes (intersexual gonads contained predominately male tissue). The degree ofintersexuality was slight，with a few primary oocytes scattered within apparently normal testicular tissue. No abnormalitieswere seen in the testes of male flounder collected at the reference site in Hokkaido or in theovaries of females from either site. Less

We have investigate the seasonal changes of serum VTG, as a biomarker of the effect of environmental estrogens, in wild male flounder (Pleuronectes yokohamae) collected from Tokyo Bay, and compare these levels to those in male flounder from a reference site along the coast of Japan. Our reference station was located off Shiriuchi in Hokkaido, where sewage and wastewater inputs to the marine environment were considered to be negligible. Pleuronectes yokohamae from Tokyo Bay, aged approximately 1 to 6 yr. were caught between January 1997 and May 1998 (male: n=130, female: n=143), covering an entire reproductive season. Reference specimens were collected off Shiriuchi, in the Strait of Tsugaru, between March 1997 and June 1998 (male: n= 62, female: n=64). Mean serum levels of VTG for female flounder from Tokyo Bay and Hokkaido suggest that no obvious difference (elevated or depressed) of VTG of females was observed between the two sites. At the reference site off Shiriuchi, the mean VTG l … More evels for male flounder was < 50 ng mlィイD1-1ィエD1. In contrast, male flounder in Tokyo Bay showed elevated levels of VTG almost throughout the year (mean: 204 ng mlィイD1-1ィエD1; ranging from < 50 ng ml ィイD1-1ィエD1 to 2200 ng mlィイD1-1ィエD1). The VTG levels in male flounder in Tokyo Bay (n=130) were significantly higher (p <0.001) compared to those of the reference fish from Hokkaido (n=62). The considerable variation in serum VTG concentration observed in individual males from Tokyo Bay could be due to individual differences in sensitivity to or degree of accumulation of estrogenic compounds.The relationship between VTG in male flounder from Tokyo Bay and other factors such as standard length, hepatosomatie index (HSI), 17β-estradiol (EィイD22ィエD2), testosterone (T), and gonadosomatic index (GSI) was investigated. We found no significant relationship between VTG and standard length which indicates that induction of VTG occurs among male flounder of all ages above one year. Furthermore, no relationship was observed between VTG and HSI, EィイD22ィエD2 or T levels. However, high concentrations of serum VTG were observed more often in male flounder whose GSI was lower than 2% in Tokyo Bay. The GSI is therefore an additional factor that should be considered when male flounder is deployed as biomonitor of environmental estrogens.The development of a very sensitive method for the determination of very low levels of plasma VTG in male fish allows, a) detection of trace amounts of estrogenic compounds and mainly, b) analysis of highly diluted serum samples, which can avoid a critical problem of the ELISA technique, the unspecific interference with serum compounds at high concentrations. We developed and optimized a luminometric immunoassay that was able to detect trace amounts of VTG in the serum of male flounder collected from a reference site, located off Shiriuchi in Hokkaido, where sewage and wastewater inputs to the marine environment were considered negligible. This method can be applied successfully to monitor seasonal changes in baseline VTG levels in serum samples obtained from a reference site. Such results will be useful in interpreting the effects of environmental estrogens in ecosystems.Both EィイD22ィエD2 and T in the sera of male and female fish were high during winter, when VTG levels in female fish and the GSI of both sexes were also high. Estrogen has been found in the blood of wild males at levels as high as 10% of those normally seen in mature females in winter. The detectable levels of VTG in the blood of wild male flounder at the reference site in winter may be a consequence of the presence of physiologically active levels of estrogen. Perhaps this species expresses VTG in both sexes in response to "natural" circulating EィイD22ィエD2.Histological analysis revealed that the gonads of about 15% of male flounder (3 out of 20) collected off Haneda in Tokyo Bay contained female gametes (intersexual gonads contained predominately male tissue). The degree of intersexuality was slight, with a few primary oocytes scattered within apparently normal testicular tissue. No abnormalities were seen in the testes of male flounder collected at the reference site in Hokkaido or in the ovaries of females from either site. Less