Ortiz-Delgado J B, Behrens A, Segner H, Sarasquete C
Instituto de Ciencias Marinas de Andalucía (CSIC), Campus Universitario Río San Pedro s/n. Apdo. Oficial, 11510 Puerto Real, Cádiz, Spain.
Ecotoxicol Environ Saf. 2008 Jan;69(1):80-8. doi: 10.1016/j.ecoenv.2006.12.021. Epub 2007 Feb 21.
The purpose of this study was to compare xenobiotic CYP1A induction in liver, gills, and excretory kidney of gilthead seabream, Sparus aurata. Fishes were exposed via water for 20 days to different concentrations of benzo(a)pyrene (B(a)P) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). CYP1A was measured at the enzyme activity level as 7-ethoxyresorufin-O-deethylase (EROD) activity, and at the protein level by means of ELISA. The liver displayed the highest absolute levels of EROD activity, both under non-exposed and exposed conditions. Organ- or inducer-related differences in the time course of CYP1A induction were moderate; however, the magnitude of the induction response varied between the organs and between B(a)P and TCDD. In the case of TCDD, liver, and kidney yielded a comparable induction response, whereas in the case of B(a)P, the kidney showed a substantially higher maximum induction factor than the liver. In the gills, the two xenobiotics resulted in similar maximum induction factors. In B(a)P-exposed seabream, EROD activities and CYP1A protein levels showed a good correlation in all three organs, whereas with TCDD as inducer the correlation was poor, what was mainly due to a decrease of EROD activities at the higher concentrations of TCDD, while CYP1A protein levels showed no concomitant decline. Overall, the study revealed both similarities and differences in the time-, concentration-, and inducer-dependent CYP1A responses of the three target organs, liver, kidney, and gills. Although, the findings of this study principally confirm the notion of the liver as the major metabolic organ in fish, they also provide evidence for substantial metabolic potential in gills and particularly in the kidney.
本研究的目的是比较金头鲷（Sparus aurata）肝脏、鳃和排泄性肾脏中异生素CYP1A的诱导情况。将鱼通过水暴露于不同浓度的苯并(a)芘（B(a)P）或2,3,7,8-四氯二苯并对二恶英（TCDD）中20天。通过7-乙氧基异吩恶唑酮-O-脱乙基酶（EROD）活性在酶活性水平测定CYP1A，并通过酶联免疫吸附测定法在蛋白质水平进行测定。在未暴露和暴露条件下，肝脏均显示出最高的EROD活性绝对水平。CYP1A诱导时间进程中的器官或诱导剂相关差异较为适度；然而，诱导反应的幅度在各器官之间以及B(a)P和TCDD之间有所不同。就TCDD而言，肝脏和肾脏产生了相当的诱导反应，而对于B(a)P，肾脏显示出比肝脏高得多的最大诱导因子。在鳃中，这两种异生素产生了相似的最大诱导因子。在暴露于B(a)P的金头鲷中，所有三个器官中的EROD活性和CYP1A蛋白质水平均显示出良好的相关性，而以TCDD作为诱导剂时，相关性较差，这主要是由于在较高浓度的TCDD下EROD活性降低，而CYP1A蛋白质水平并未随之下降。总体而言，该研究揭示了肝脏、肾脏和鳃这三个靶器官在时间、浓度和诱导剂依赖性CYP1A反应方面的异同。虽然本研究的结果主要证实了肝脏是鱼类主要代谢器官的观点，但它们也为鳃尤其是肾脏中的大量代谢潜力提供了证据。
