Puinean A M, Labadie P, Hill E M, Osada M, Kishida M, Nakao R, Novillo A, Callard I P, Rotchell J M
Department of Biology & Environmental Science, University of Sussex, Falmer, Brighton BN1 9QJ, UK.
Aquat Toxicol. 2006 Oct 12;79(4):376-83. doi: 10.1016/j.aquatox.2006.07.006. Epub 2006 Jul 14.
To investigate the effect of estrogenic compounds on the marine mussel Mytilus edulis, an assay was developed to measure the expression of two vertebrate estrogen responsive genes-estrogen receptor (ER) and vitellogenin (VTG) genes. Expression was measured in M. edulis gonads following a 10-day exposure to 200 ng/l 17beta-estradiol (estradiol). The concentrations of esterified estradiol in mussel tissue increased 15-fold in a time-dependent manner-confirming uptake of the compound by the mussels, however there was no significant increase of free estradiol in mussel tissues during the exposure period. The ER and VTG mRNA levels in the gonads of both sexes were measured at days 1-3, 5, and 10 in control and exposed mussels. However, no significant change in the expression of either the ER or VTG genes was recorded at any of the sampled time points. The results suggest that either a regulatory mechanism exists in a mussel that is able to maintain constant levels of free estradiol by converting the excess estradiol into esterified products which may have reduced affinity for the estrogen receptor, or alternatively, that the ER and VTG genes are unresponsive to estrogens in these organisms. The significance of these findings in terms of the utility of ER and VTG as biomarkers of endocrine disruption in bivalve species is discussed.
为了研究雌激素化合物对海洋贻贝紫贻贝的影响，开发了一种检测方法来测量两种脊椎动物雌激素反应基因——雌激素受体（ER）和卵黄蛋白原（VTG）基因的表达。在紫贻贝性腺中，将其暴露于200纳克/升的17β-雌二醇（雌二醇）10天后测量基因表达。贻贝组织中酯化雌二醇的浓度呈时间依赖性增加了15倍——证实贻贝摄取了该化合物，然而在暴露期间贻贝组织中游离雌二醇没有显著增加。在对照和暴露的贻贝中，于第1 - 3天、第5天和第10天测量了两性性腺中ER和VTG的mRNA水平。然而，在任何采样时间点，均未记录到ER或VTG基因表达的显著变化。结果表明，贻贝中要么存在一种调节机制，能够通过将过量的雌二醇转化为对雌激素受体亲和力可能降低的酯化产物来维持游离雌二醇的恒定水平，要么在这些生物中ER和VTG基因对雌激素无反应。本文讨论了这些发现对于将ER和VTG用作双壳类物种内分泌干扰生物标志物的实用性的意义。
