Hewitt L Mark, Pryce Andrea C, Parrott Joanne L, Marlatt Vicki, Wood Craig, Oakes Kenneth, Van Der Kraak Glen J
Aquatic Ecosystem Protection Research Branch, National Water Research Institute, Environment Canada, Burlington, Ontario L7R 4A6, Canada.
Environ Toxicol Chem. 2003 Dec;22(12):2890-7. doi: 10.1897/02-180.
The accumulation of ligands for the aryl hydrocarbon receptor (AhR) and fish sex steroid receptors was investigated using two separate controlled fish exposures to final effluent from a bleached sulfite/groundwood mill in New Brunswick, Canada. In the first experiment, hepatic tissue extracts from exposed fish were fractionated according to lipophilicity. Fractions with different octanol-water (Kow) partition coefficients were tested for the presence of bioavailable chemicals that function as ligands for the AhR in H4IIE cells, rainbow trout hepatic estrogen receptors (ER), goldfish testicular androgen receptors (AR), and goldfish sex steroid binding protein (SSBP). Fish accumulated ligands for each receptor after 4-d exposure to effluent. Single fractions contained ligands for the AhR and the ER, while multiple fractions competed for the AR and SSBP. Fish also accumulated ligands for the AhR and SSBP from Saint John River dilution water, indicating upstream sources of bioactive substances. Semipermeable-membrane devices deployed concurrently with fish accumulated ligands from effluent for all receptors except the ER. In the second experiment, accumulated ligands were evaluated after exposure of fish to effluent for two different durations and following a depuration period. Hepatic mixed function oxygenase activity and whole-liver hormonal activity, measured as binding to SSBP, returned to background following 6 d depuration and were reduced but still significant after 12-d exposure to effluent. Whole-liver extract affinities for the AR were maintained after extended exposure and depuration, indicating the potential for AR ligands to bioaccumulate. The accumulation of AhR ligands and ligands for sex steroid receptors provides a mechanistic linkage to effects on growth, development, and performance of fish exposed to effluent from this and other mills.
利用两组独立的受控鱼类暴露实验，研究了加拿大新不伦瑞克省一家亚硫酸盐漂白/磨木浆厂最终废水对芳烃受体（AhR）和鱼类性类固醇受体配体的累积情况。在第一个实验中，对暴露于废水中的鱼类肝脏组织提取物按亲脂性进行分级分离。对具有不同正辛醇-水（Kow）分配系数的级分，检测其中是否存在可作为H4IIE细胞中AhR配体、虹鳟肝脏雌激素受体（ER）、金鱼睾丸雄激素受体（AR）和金鱼性类固醇结合蛋白（SSBP）配体的生物可利用化学物质。鱼类在暴露于废水4天后，每种受体都累积了配体。单个级分含有AhR和ER的配体，而多个级分与AR和SSBP竞争。鱼类还从圣约翰河稀释水中累积了AhR和SSBP的配体，表明存在生物活性物质的上游来源。与鱼类同时部署的半透膜装置从废水中累积了除ER之外所有受体的配体。在第二个实验中，在鱼类暴露于废水不同时长并经过净化期后，对累积的配体进行评估。以与SSBP结合来衡量的肝脏混合功能氧化酶活性和全肝激素活性，在净化6天后恢复到背景水平，在暴露于废水12天后虽有所降低但仍显著。长时间暴露和净化后，全肝提取物对AR的亲和力得以维持，表明AR配体具有生物累积的潜力。AhR配体和性类固醇受体配体的累积为受该工厂及其他工厂废水影响的鱼类生长、发育和性能变化提供了一种机制联系。
