Effects of 17β-estradiol and testosterone on hepatic mRNA/protein levels and catalytic activities of CYP2M1, CYP2K1, and CYP3A27 in rainbow trout (Oncorhynchus mykiss)
Effects of 17β-estradiol and testosterone on hepatic mRNA/protein levels and catalytic activities of CYP2M1, CYP2K1, and CYP3A27 in rainbow trout (Oncorhynchus mykiss)
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DOI：
10.1006/taap.1999.9016
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发表时间：
2000-10-15
影响因子：
3.8
通讯作者：
Wang-Buhler, JL
中科院分区：
文献类型：
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作者：
Buhler, DR;Miranda, CL;Wang-Buhler, JL
人们日益关注的是，接触环境中的化学品会扰乱野生动物和人类的内分泌系统，造成生殖问题或其他不利影响。许多细胞色素P450（CYP）的表达受激素控制，因此，这些酶的水平会受到内分泌干扰化学品的影响。先前的研究已经报道，用雌激素和雄激素17 β-雌二醇（E2）和睾酮（T）处理鱼和其他动物会改变处理动物中的P450含量或酶活性。然而，许多这些研究的结果是不完整的或不一致的，在大多数情况下，对特定的P450形式的影响尚未确定。因此，为了更好地了解性腺激素对P450表达及其相关酶活性的影响，有兴趣进行全面的调查，三个组成性肝P450在虹鳟鱼（虹鳟鱼）的转录和翻译表达激素暴露后。因此，在第1、4、7、13和15天，用丙二醇媒介物和最具活性的雌激素和雄激素E2（3 mg/kg）或T（3 mg/kg）腹膜内注射幼鳟鱼，并在第19天实施安乐死。在用E2处理后，肝微粒体显示出显著降低的水平，（对照百分比）总P450含量（52%）、月桂酸羟化酶（32%）和6 β-孕酮羟化酶活性（27%）、[H-3]黄曲霉毒素-DNA结合（31%）以及单个细胞色素P450（CYP）LMC 1（CYP 2 M1）、LMC 2（CYP 2K 1）、和LMC 5（CYP 3A 27）（三种亚型的平均值降低至对照值的29%），性别间仅存在微小差异。用T处理没有影响或导致雄性中总P450（42%）、雌性中月桂酸羟化酶（24%）和雄性中6 β-孕酮羟化酶活性（21%）的小幅增加。鱼之间的生物变异性很高，非多态性或新的LMC 2样形式被检测到在一些肝微粒体样品中约52 kDa的鱼暴露后，以任何激素。通过北方印迹分析雌性肝脏RNA，在E2处理的鳟鱼中，CYP 2 M1、CYP 2K 1和CYP 3A 27 mRNA水平平均降低94%。在T处理的鳟鱼肝脏中，CYP 2 M1和CYP 3A 27的mRNA水平变化不大，但CYP 2K 1的mRNA水平下降约60%。在一些鱼中，对于两种激素处理，在约2.8 kb处观察到额外的CYP 2K 1 cDNA可杂交mRNA作为微弱条带。因此，本研究的结果表明，E2下调，而T产生的小，但可变的影响肝脏mRNA/蛋白质水平的CYP 2K 1，CYP 2 M1，和CYP 3A 27在青少年虹鳟鱼。因此，这项研究表明，鱼类和其他野生动物暴露于环境内分泌干扰物，特别是雌激素模拟物，可以通过涉及特定P450同工酶表达水平改变的机制对一些生理过程产生不利影响。(C)北京大学出版社.
There is growing concern that exposure to chemicals in the environment can disrupt the endocrine systems of wildlife and humans, causing reproductive problems or other adverse effects. The expression of many cytochrome P450s (CYPs) is under hormonal control, hence, levels of these enzymes can be affected by exposure to endocrine-disrupting chemicals. Previous research has reported that treatment of fish and other animals with the estrogenic and androgenic hormones 17 beta -estradiol (E2) and testosterone (T) alters the P450 content or enzyme activities in the treated animals. However, the results of many of these studies are either incomplete or in disagreement and in most cases the effect on specific P450 forms has not been determined. Therefore, to better understand the effects of gonadal hormones on the expression of P450s and their associated enzyme activities, it was of interest to undertake a comprehensive investigation of the transcriptional and translational expression of three constitutive hepatic P450s in the rainbow trout (Oncorhynchus mykiss) following hormone exposure. Accordingly, juvenile trout were injected intraperitoneally with propylene glycol vehicle and the most active estrogenic and androgenic hormones E2 (3 mg/kg) or T (3 mg/kg) on days 1, 4, 7, 13, and 15 and euthanized on day 19. After treatment with E2, hepatic microsomes showed significantly lower levels (percentage of control) in total P450 contents (52%), lauric acid hydroxylase (32%), and 6 beta -progesterone hydroxylase activities (27%), [H-3]aflatoxin-DNA binding (31%), and the protein levels of individual cytochrome P450s (CYPs) LMC1 (CYP2M1), LMC2, (CYP2K1), and LMC5 (CYP3A27) (average for three isoforms a reduction to 29% of control values) with only minor differences between sexes. Treatment with T had either no effect or resulted in small increases in total P450 in males (42%), in lauric acid hydroxylase in females (24%), and in 6 beta -progesterone hydroxylase activity in males (21%). Biological variabilities among fish were high and apolymorphic or new LMC2-like form was detected at about 52 kDa in some liver microsomal samples after exposure of fish to either hormone. Female liver RNAs were analyzed through Northern blots and an average decrease of 94% in CYP2 M1, CYP2K1, and CYP3A27 mRNA levels occurred in the E2-treated trout. In livers from T-treated trout, the changes of mRNA levels of CYP2M1 and CYP3A27 were negligible, but CYP2K1 mRNA level decreased by about 60%. Additional CYP2K1 cDNA hybridizable mRNAs were seen in some fish as faint bands at about 2.8 kb for both hormone treatments. Results of this study, therefore, indicated that E2 down-regulated while T produced small but variable effects on the hepatic mRNA/protein levels of CYP2K1, CYP2M1, and CYP3A27 in juvenile rainbow trout. This study, therefore, suggests that exposure of fish and other wildlife to environmental endocrine disrupters, especially estrogen mimics, can adversely affect a number of physiological processes through mechanisms involving altered levels of expression of specific P450 isozymes. (C) 2000 Academic Press.