■药物残留在水生环境中被广泛检测到,并且可以被鱼类等非目标物种吸收。细胞色素P450(CYP)代表了鱼类的重要解毒机制,就像人类一样。在本研究中,我们评估了虹鳟鱼CYP1A和CYP3A同源物的底物选择性与人类,通过测定总共16种人类药物对CYP1A样乙氧基间苯二酚O-脱乙基酶(EROD)和CYP3A样7-苄氧基-4-三氟甲基香豆素O-脱苄基酶(BFCOD)的半数最大抑制浓度(IC50)在虹鳟鱼(Oncorhynchusmykiss)肝S9级分(RT-S9)中。
■托莫西汀的抑制作用(IC50),阿托伐他汀,氮卓斯汀,比马前列素,clomethiazole,氯氮平,地氯雷他定,双硫仑,埃索美拉唑,Felbinac,氟卡尼,orphenadrine,哌唑嗪,喹硫平,舒必利,和佐米曲坦对EROD和BFCOD活性在RT-S9使用IC50位移测定法测定,能够识别时间依赖性抑制剂(TDI)。此外,使用平衡透析评估受试药物与RT-S9的非特异性结合.
■大多数测试药物是RT-S9中EROD和BFCOD活性的中度至弱抑制剂,即使大多数是非人CYP1A或CYP3A的抑制剂。只有比马前列素,clomethiazole,Felbinac,舒必利,佐米曲坦在RT-S9中没有抑制任何一种活性。EROD抑制作用通常强于BFCOD和某些物质(托莫西汀,氟卡尼,和哌唑嗪)仅选择性抑制EROD活性。使用氮卓斯汀和埃索美拉唑检测到最强的EROD抑制作用(未结合的IC50为3.8±0.5µM和3.0±0.8µM,分别)。测试物质均不是BFCOD的TDI,但埃索美拉唑是EROD的TDI.除了氯甲噻唑和双硫仑,测试药物与RT-S9的非特异性结合广泛(未结合分数<0.5),并且与其水-辛醇分配系数密切相关(R2=0.7135)。
■结果表明,无法根据人类数据明确预测RT-S9中的P450相互作用,但是本文报道的体外数据可以揭示虹鳟鱼CYP1A1和CYP3A27与其人类同源物相比的底物选择性。然而,IC50浓度比药物的平均环境浓度高许多数量级。埃索美拉唑对EROD的时间依赖性抑制作用可能需要进一步研究,以评估其与肝毒性对鱼类影响的可能相互联系。
UNASSIGNED: Pharmaceutical residues are widely detected in aquatic environment and can be taken up by nontarget species such as fish. The cytochromes P450 (CYP) represent an important detoxification mechanism in fish, like in humans. In the present study, we assessed the correlation of the substrate selectivities of rainbow trout CYP1A and CYP3A homologues with those of human, through determination of the half-maximal inhibitory concentrations (IC50) of a total sixteen human pharmaceuticals toward CYP1A-like ethoxyresorufin O-deethylase (EROD) and CYP3A-like 7-benzyloxy-4-trifluoromethylcoumarin O-debenzylase (BFCOD) in rainbow trout (Oncorhynchus mykiss) liver S9 fractions (RT-S9).
UNASSIGNED: The inhibitory impacts (IC50) of atomoxetine, atorvastatin, azelastine, bimatoprost, clomethiazole, clozapine, desloratadine, disulfiram, esomeprazole, felbinac, flecainide, orphenadrine, prazosin, quetiapine, sulpiride, and zolmitriptan toward the EROD and BFCOD activities in RT-S9 were determined using the IC50 shift assay, capable of identifying time-dependent inhibitors (TDI). Additionally, the nonspecific binding of the test pharmaceuticals to RT-S9 was assessed using equilibrium dialysis.
UNASSIGNED: Most test pharmaceuticals were moderate to weak inhibitors of both EROD and BFCOD activity in RT-S9, even if most are noninhibitors of human CYP1A or CYP3A. Only bimatoprost, clomethiazole, felbinac, sulpiride, and zolmitriptan did not inhibit either activity in RT-S9. EROD inhibition was generally stronger than that of BFCOD and some substances (atomoxetine, flecainide, and prazosin) inhibited selectively only EROD activity. The strongest EROD inhibition was detected with azelastine and esomeprazole (unbound IC50 of 3.8 ± 0.5 µM and 3.0 ± 0.8 µM, respectively). None of the test substances were TDIs of BFCOD, but esomeprazole was a TDI of EROD. Apart from clomethiazole and disulfiram, the nonspecific binding of the test pharmaceuticals to the RT-S9 was extensive (unbound fractions <0.5) and correlated well (R 2 = 0.7135) with their water-octanol distribution coefficients.
UNASSIGNED: The results indicate that the P450 interactions in RT-S9 cannot be explicitly predicted based on human data, but the in vitro data reported herein can shed light on the substrate selectivity of rainbow trout CYP1A1 and CYP3A27 in comparison to their human homologues. The IC50 concentrations are however many orders of magnitude higher than average environmental concentrations of pharmaceuticals. The time-dependent EROD inhibition by esomeprazole could warrant further research to evaluate its possible interlinkages with hepatotoxic impacts on fish.