Brüschweiler B J, Würgler F E, Fent K
Swiss Federal Institute for Environmental Science and Technology (EAWAG), Dübendorf, Switzerland.
Arch Environ Contam Toxicol. 1996 Nov;31(4):475-82. doi: 10.1007/BF00212430.
The interactions in vitro of heavy metals Cd(II), Co(II), Cu(II), Ni(II), Pb(II), and Zn(II) with cytochrome P4501A (CYP1A) induction response and enzyme activity were studied in fish hepatoma cells PLHC-1. Cells were simultaneously exposed to heavy metals and to 3-methylcholanthrene (3-MC), an inducer of CYP1A. Heavy metals were added to the cells in different concentrations. Cytotoxicity were measured in the neutral red (NR) assay, relative CYP1A protein contents in an enzyme-linked immunosorbent assay (ELISA), and CYP1A activities in the ethoxyresorufin-O-deethylase (EROD) assay. All metals had a more pronounced effect on EROD activity than on CYP1A protein content and cytotoxicity. For the most active metal Cd(II), a 50% inhibition of EROD activity was observed at significantly lower concentrations (2.2 x 10(-5) M) than a 50% reduction of CYP1A protein (5.3 x 10(-5) M), and a 50% cytotoxicity (1.4 x 10(-4) M). The inhibitory potency of the metals had the following order: Cd(II) > Ni(II) > Cu(II) > Co(II) = Zn(II) > Pb(II). In a second set of experiments, lysates of 3-MC-induced cells were exposed to heavy metals. Cd(II) and Cu(II) caused a 50% inhibition of EROD activity at significantly lower concentrations than in the experiments with living cells, at 8.2 x 10(-6) M and 1.3 x 10(-5) M, respectively, whereas the effect by Co(II) occurred at a significantly higher concentration (8.2 x 10(-4) M). The results indicate that Cd(II) and Cu(II) in particular may affect the CYP1A system of the liver of fish at low concentrations through direct inhibition of the CYP1A enzyme activity. CYP1A induction response in fish liver is increasingly being used in biomonitoring programs. In the environment, interactions of CYP1A-inducing and CYP1A-inhibiting components (such as heavy metals) can be expected and must be taken into consideration.
在鱼类肝癌细胞PLHC-1中研究了重金属镉（II）、钴（II）、铜（II）、镍（II）、铅（II）和锌（II）与细胞色素P4501A（CYP1A）诱导反应及酶活性的体外相互作用。细胞同时暴露于重金属和CYP1A诱导剂3-甲基胆蒽（3-MC）中。向细胞中添加不同浓度的重金属。通过中性红（NR）试验测定细胞毒性，通过酶联免疫吸附测定（ELISA）测定相对CYP1A蛋白含量，通过乙氧异吩唑酮-O-脱乙基酶（EROD）试验测定CYP1A活性。所有金属对EROD活性的影响比对CYP1A蛋白含量和细胞毒性的影响更显著。对于活性最高的金属镉（II），观察到其对EROD活性的50%抑制浓度（2.2×10⁻⁵ M）显著低于CYP1A蛋白降低50%的浓度（5.3×10⁻⁵ M）和细胞毒性降低50%的浓度（1.4×10⁻⁴ M）。金属的抑制效力顺序如下：镉（II）＞镍（II）＞铜（II）＞钴（II） = 锌（II）＞铅（II）。在第二组实验中，将3-MC诱导细胞的裂解物暴露于重金属中。镉（II）和铜（II）对EROD活性的50%抑制浓度分别为8.2×10⁻⁶ M和1.3×10⁻⁵ M，显著低于活细胞实验中的浓度，而钴（II）的影响则在显著更高的浓度（8.2×10⁻⁴ M）下出现。结果表明，镉（II）和铜（II）尤其可能在低浓度下通过直接抑制CYP1A酶活性影响鱼类肝脏的CYP1A系统。鱼类肝脏中的CYP1A诱导反应越来越多地用于生物监测项目。在环境中，可以预期CYP1A诱导成分和CYP1A抑制成分（如重金属）之间的相互作用，并且必须予以考虑。
