Cocktail探针药物法评价灯盏花素对大鼠CYP450体内代谢活性的影响

目的用Cocktail探针药物法研究灯盏花素对大鼠CYP1A2、CYP2C9、CYP2E1和CYP2D6体内代谢活性的影响。方法将大鼠随机分为3组,空白对照组、低剂量组和高剂量组。低剂量组和高剂量组分别尾静脉给予灯盏花素粉针剂1.8,5.4 mg.kg-1.d-1,空白对照组给予生理盐水,共14 d。各组分别于第15 d注射Cocktail探针溶液,用HPLC检测各探针药物的血药浓度,用DAS2.0计算药代动力学参数,评价相应的CYP450亚型的体内代谢活性。结果高剂量组美托洛尔的AUC和t1/2显著高于空白对照组,CL显著低于空白对照组(P<0.05)。低剂量组美托洛尔虽然也有相同趋势,但差异无统计学意义(P>0.05)。各组咖啡因、氯唑沙宗和甲苯磺丁脲的主要药代动力学参数均无显著差异(P>0.05)。结论高剂量灯盏花素粉针剂可明显抑制大鼠CYP2D6的体内代谢活性,而对CYP1A2、CYP2E1和CYP2C9无显著性影响。     

Cocktail探针药物法评价威麦宁胶囊对大鼠体内CYP450活性的影响

目的采用Cocktail探针药物法评价威麦宁胶囊对大鼠体内6种CYP450亚型酶活性的影响。方法分别选用甲苯磺丁脲、氯唑沙宗、茶碱、咪达唑仑、奥美拉唑和右美沙芬作为CYP2C6、CYP2E1、CYP1A2、CYP3A2、CYP2D1和CYP2D2的探针底物。大鼠每日灌胃威麦宁胶囊1.6 g·kg-1,采用LC-MS/MS测定给药前后大鼠体内6种混合探针的血药浓度,计算药动学参数。结果威麦宁胶囊连续给药2周后,与给药前相比,奥美拉唑ρmax、AUC0-t、tmax及AUC0-∞显著升高(P<0.05);咪达唑仑ρmax、AUC0-t和AUC0-∞显著升高(P<0.01或P<0.05);右美沙芬ρmax、AUC0-t升高(P<0.05);甲苯磺丁脲t1/2、AUC0-∞和tmax显著升高(P<0.01或P<0.05),而CL/F显著降低(P<0.01),ρmax、AUC0-t无显著改变(P>0.05);氯唑沙宗ρmax升高(P<0.05),CL/F降低(P<0.05),AUC0-t升高但无显著差异(P>0.05);茶碱ρmax、AUC0-t升高但无显著差异(P>0.05)。表明奥美拉唑、咪达唑仑和右美沙芬代谢明显减慢(均P<0.05),茶碱、甲苯磺丁脲、氯唑沙宗的代谢无显著差异;威麦宁胶囊对大鼠体内CYP2D1、CYP3A2、CYP2D2酶有抑制作用,对CYP1A2、CYP2C6、CYP2E1酶的活性无显著影响。结论当威麦宁胶囊与CYP2C19、CYP3A4、CYP2D6酶的底物药物合用时,需要调整给药剂量,避免因药物相互作用使体内血药浓度过高产生毒副作用。     

Cocktail法评价白香丹胶囊对大鼠体内CYP450酶活性的影响

目的：建立同时测定大鼠血浆中6种CYP450探针药物的方法,并采用Cocktail法研究白香丹胶囊对大鼠CYP450酶活性的影响。方法：选用茶碱(CYP1A2)、氯唑沙宗(CYP2E1)、甲苯磺丁脲(CYP2C6)、右美沙芬(CYP2D2)、奥美拉唑(CYP2D1)、咪达唑仑(CYP3A2)作为探针药物。大鼠随机分为对照组和给药组,给药组每天灌胃白香丹胶囊0.675 g?kg-1,对照组灌胃等量生理盐水,连续给药14天。第15天均灌胃给予6个探针药物,于不同时间点眼眶取血,采用LC-MS/MS法测定各探针药物浓度,计算药动学参数并进行组间t检验。结果：与对照组相比,给药组茶碱(P < 0.01)、氯唑沙宗(P < 0.01)、甲苯磺丁脲(P < 0.05)代谢显著加快,右美沙芬、奥美拉唑、咪达唑仑代谢无显著性差异。结论：白香丹胶囊对大鼠CYP1A2有中强诱导作用,对CYP2E1、CYP2C6有弱诱导作用。     

混合探针法评价白香丹胶囊对大鼠体内CYP450酶活性的影响

目的：建立同时测定大鼠血浆中6种CYP450探针药物的方法,并采用Cocktail法研究白香丹胶囊对大鼠CYP450酶活性的影响。方法：选用茶碱（CYP1A2）、氯唑沙宗（CYP2E1）、甲苯磺丁脲（CYP2C6）、右美沙芬（CYP2D2）、奥美拉唑（CYP2D1）、咪达唑仑（CYP3A2）作为探针药物。大鼠随机分为对照组和给药组,给药组每天灌胃白香丹胶囊0.675 g·kg-1,对照组灌胃等量生理盐水,连续给药14 d。第15天均灌胃给予6个探针药物,于不同时间点眼眶取血,采用LC-MS/MS法测定各探针药物浓度,计算药动学参数并进行组间t检验。结果：与对照组相比,给药组茶碱（P<0.01）、氯唑沙宗（P<0.01）、甲苯磺丁脲（P<0.05）代谢显著加快;右美沙芬、奥美拉唑、咪达唑仑代谢无显著性差异。结论：白香丹胶囊对大鼠 CYP1A2有中强诱导作用,对CYP2E1、CYP2C6有弱诱导作用。     

Cocktail探针药物法评价生、醋莪术对CYP450酶亚型的影响

目的用Cocktail探针药物法,研究生、醋莪术对大鼠CYP1A2、CYP3A4和CYP2E1活性的影响并进行比较,探讨其通过炮制增强或改变作用的趋向性。方法将SD大鼠随机分组,生、醋莪术组分别给予生、醋莪术提取液(9 g.kg-1),以生理盐水为空白对照,在一定时间点采集血样,用HPLC检测探针药物在大鼠体内的代谢情况,以评价生、醋莪术对CYP450酶的影响。结果生莪术的茶碱、氨苯酚和氯唑沙宗的代谢情况与空白组相比差异无显著性;但醋莪术与空白组相比,茶碱和氯唑沙宗的T12、Tmax和AUC明显增加,CL/F明显降低;氨苯酚的T12变化不明显,AUC明显降低,CL/F明显增加;氯唑沙宗的T12、Tmax、AUC明显增加,CL/F明显降低。结论单次给予大鼠生、醋莪术后,生莪术对CYP450酶的作用不明显,醋莪术对CYP1A2和CYP2E1具有抑制作用,对CYP3A4具有诱导作用。     

天然冰片对大鼠细胞色素P450四种亚型活性的影响

目的：用Cocktail探针药物法研究天然冰片对大鼠细胞色素P450四种亚型CYP1A2、CYP2C6/11、CYP2E1和CYP3A活性的影响。方法：将大鼠随机分为2组,给药组灌胃给予天然冰片-0.8%CMC-Na混悬液,剂量90mg/kg,对照组灌胃给予不含药物的0.8%CMC-Na溶液,每天1次,连续7d。于第8天,两组大鼠均尾静脉注射混合探针药物溶液（茶碱10mg/kg、甲苯磺丁脲2.5mg/kg、氯唑沙宗10mg/kg、氨苯砜5mg/kg）,眼内眦静脉采血,超高效液相色谱法检测各探针药物的血药浓度,采用WinNonlin 5.0.1计算药代动力学参数。结果：与对照组相比,天然冰片组中甲苯磺丁脲的t1/2、AUC0-t、AUC0-∞和MRT0-∞明显减小,两组之间的差异具有统计学意义（P〈0.05）;而两组之间茶碱、氯唑沙宗和氨苯砜的药代动力学参数则没有明显差异。结论：天然冰片对大鼠CYP2C6/11的活性具有诱导作用,对CYP1A2、CYP2E1和CYP3A活性无显著影响。     

丹参-红花药对配伍前后对大鼠肝药酶亚型CYP1A2、CYP2E1和CYP3A4活性的影响

目的 研究丹参、红花药对配伍前后对大鼠肝药酶亚型CYP1A2、CYP2E1和CYP3A4活性的影响。方法 分别选用咖啡因、氯唑沙宗和咪达唑仑作为CYP1A2、CYP2E1和CYP3A4的探针药物。将大鼠随机分为4组,即空白对照组、丹参（1.2 g生药/kg）组、红花（0.4 g生药/kg）组、丹参（1.2 g生药/kg）+红花（0.4 g生药/kg）组,按上述剂量ig给药7 d。于末次给药后30 min,尾iv探针药物咖啡因、氯唑沙宗和咪达唑仑溶液,在不同的时间点取血进行检测;以甲硝唑为内标,采用HPLC法检测探针药物咖啡因、氯唑沙宗和咪达唑仑的量,评价各药物组对大鼠CYP3A4、CYP2E1和CYP1A2活性的影响。结果 与空白对照组比较,丹参组咖啡因、氯唑沙宗和咪达唑仑的清除率（CL）有所增强,曲线下面积（AUC）减少,其半衰期（t_1/2）有减少趋势,但差异均不显著;红花组咖啡因和氯唑沙宗的CL有所降低,但差异不显著,咪达唑仑的CL显著降低（P<0.01）,氯唑沙宗的AUC增加,但差异不显著,咖啡因和咪达唑仑的AUC明显增加（P<0.05、0.01）;丹参+红花组咖啡因和氯唑沙宗的CL明显降低（P<0.05）,曲线下面积（AUC）明显增加（P<0.05）,其t_1/2有延长趋势,但差异不显著。结论 丹参、红花配伍后对CYP450亚型CYP1A2和CYP2E1有抑制作用,这可能是丹参、红花配伍协同增效的作用机制之一。     

复方银杏叶胶囊对肝损伤大鼠CYP2E1、CYP3A4的影响

目的研究复方银杏叶胶囊(CGB)对酒精性肝损伤大鼠CYP2E1、CYP3A4活性的影响。方法正常组和酒精性肝损伤模型组均以CGB[(250 mg/(kg.d)]灌胃,分别在灌胃CGB前及灌胃1周后,灌胃探针药氯唑沙宗(50 mg/kg)及氨苯砜(20 mg/kg),于探针药灌后24 h内不同时间点采血,测定各探针药血药浓度。结果灌胃CGB前,模型组氯唑沙宗和氨苯砜的AUC0-24、Cmax均显著低于正常组(P<0.05或P<0.01)。灌胃CGB后,模型组氯唑沙宗和氨苯砜的AUC0-24、Cmax均较灌胃前显著升高(P<0.05或P<0.01);且氯唑沙宗的t1/2灌胃CGB后明显高于灌胃前(P<0.05)。结论 CGB能够明显抑制酒精性肝损伤大鼠CYP2E1、CYP3A4酶活性。     

Cocktail探针法测定南沙参与藜芦配伍对大鼠CYP450亚酶活性的影响

目的利用Cocktail探针法,测定南沙参与藜芦配伍对大鼠CYP1A2、CYP3A4、CYP2C9和CYP2C19酶活性的影响,从药物相互作用角度探寻二者配伍增毒相反的体内证据。方法将24只雄性Wistar大鼠随机分组,南沙参组、藜芦组、合用组分别灌胃南沙参煎液(13.5g.kg-1)、藜芦煎液(0.81g.kg-1)、合煎液(14.31g.kg-1),空白组灌胃生理盐水,连续给药7天,于第8天尾静脉注射混合探针药物后于不同时间点采集血样;血样经处理后利用HPLC同时测定不同时间点各探针药物的血药浓度,通过WinNolin5.2软件计算各探针药物的药动学参数,并进行组间比较,进而反映亚酶活性在各组之间的差异。结果与空白对照相比,藜芦组可降低甲苯磺丁脲的AUC(0～t),增加其Vz;南沙参组可降低咖啡因的AUC(0～∞),显著降低甲苯磺丁脲的AUC(0～t)、AUC(0～∞)并使其Vz,CL显著增加,对氨苯砜、奥美拉唑的各药动学参数无明显影响;与藜芦组相比,合用可增加氨苯砜的MRT(0～t),降低奥美拉唑的AUC(0～t),AUC(0～∞)并增加其CL;与南沙参组相比,合用可增加甲苯磺丁脲的AUC(0～t),降低其Vz,CL。结论与空白组相比,藜芦组对大鼠CYP2C9具有诱导作用,南沙参组对大鼠CYP1A2酶具有诱导作用,对CYP2C9酶具有显著诱导作用,对CYP3A4、CYP2C19无明显影响;与藜芦组相比,合用组对大鼠CYP3A4酶具有抑制作用,对CYP2C19酶具有诱导作用;与南沙参组相比,合用组对大鼠CYP2C19酶具有抑制作用。     

鸡尾酒法评价石蒜对大鼠细胞色素P450酶活性的影响

目的 运用鸡尾酒法评价石蒜对细胞色素P450酶活性的影响。方法 将大鼠随机分为对照组和石蒜低、高剂量组。对照组给予生理盐水，石蒜低、高剂量组大鼠灌胃给药0.5，1.0 g·kg^-1石蒜，连续给药15 d。然后第16天给予探针药物，UPLC-MS/MS检测探针药浓度。结果 与对照组对比，石蒜低剂量组和高剂量组的安非他酮AUC_（0-t）、C_max都显著升高（P<0.05），CL_z/F显著降低（P<0.05）。与对照组对比，石蒜高剂量组的美托洛尔、咪达唑仑和非那西丁AUC_（0-t）显著降低（P<0.05）、CL_z/F显著升高（P<0.05），而低剂量组与对照组比较差异无统计学意义。与对照组对比，石蒜组的甲苯磺丁脲AUC_（0-t）、CL_z/F差异无统计学意义，C_max显著降低（P<0.05）。结论 石蒜能抑制大鼠CYP2B1酶活性，诱导大鼠CYP2D1、CYP3A2和CYP1A2酶活性，稍有诱导大鼠CYP2C11酶活性的作用。     

Biotransformation of caffeine by cDNA-expressed human cytochromes P-450

Objectives: The biotransformation of caffeine has been studied in vitro using human cytochrome P-450 isoenzymes (CYPs) expressed in human B-lymphoblastoid cell lines, namely CYP1A1, 1A2, 2A6, 2B6, 2D6-Val, 2E1 and 3A4, and microsomal epoxide hydroxylase (EH). In addition, CYP 2D6-Met was also studied, in which a valine in the wild type (CYP2D6-Val) has been replaced by a methionine due to a G to A mutation in position 112. Results: At caffeine 3 mmol·l^-1, five CYPs (1A1, 1A2, 2D6-Met, 2E1 and 3A4) catalysed the biotransformation of caffeine. Among the enzymes studied, CYP1A2, which predominantly catalysed paraxanthine formation, had the highest intrinsic clearance (160 l h^-1·mmol^-1 CYP). Together with its high abundance in liver, it should be considered, therefore, to be the most important isoenzyme in caffeine metabolism. The affinity of caffeine for CYP1A1 was comparable to that of its homologue 1A2. CYP2D6-Met, which catalysed caffeine metabolism by demethylation and 8-hydroxylation, also had a relatively high intrinsic clearance (3.0 l·h^-1mmol^-1 CYP), in particular for theophylline and paraxanthine formation, with k_M values between 9–16 mmol·l^-1. In contrast, the wild type, CYP2D6-Val, had no detectable activity. In comparison, CYP2E1 played a less important role in in vitro caffeine metabolism. CYP3A4 predominantly catalysed 8-hydroxylation with a k_M value of 46 mmol·l^-1 and an intrinsic clearance of 0.60 l·h^-1·mmol^-1 CYP. Due to its high abundance in human liver, the latter CYP may contribute significantly to the in vivo formation of TMU. Conclusion: The findings of this study indicate that i) microsomes from transfected human B-lymphoblastoid cell lines give results close to those obtained with microsomes isolated from human liver, ii) at least four CYP isoforms are involved in caffeine metabolism, iii) at a substrate concentration <0.1 mmol·l^-1, CYP1A2 and 1A1 are the most important isoenzymes, iv) at higher concentrations the participation of other isoenzymes, in particular CYP3A4, 2E1 and possibly also CYP2D6-Met, are important in caffeine metabolism, and v) the nucleotide composition at position 1120 of CYP2D6 determines the activity of this isoenzyme in caffeine metabolism.Abbreviations AFMU 5-acetylamino-6-formylamino-3-methyluracil - CYP human cytochrome P-450 - PAH polycyclic aromatic hydrocarbon - 17X paraxanthine - 37X theobromine - 13X theophylline - 137U trimethyluric acid.     

Effects of Guanxinning injection on rat cytochrome P450 isoforms activities in vivo and in vitro

Abstract

1. We aimed to investigate the regulatory effects of Guanxinning injection (GXNI) on activities of cytochrome P1A2 (CYP1A2), CYP2C11, CYP2D1 and CYP3A1/2 by probe drugs in rats in vivo and in vitro.

2. GXNI-treated and blank control groups were administered GXNI and physiological saline by caudal vein for 14 days consecutively, then they were given the probe drugs of caffeine (10?mg/kg), tolbutamide (10?mg/kg), metoprolol (20?mg/kg) and dapsone (10?mg/kg) by intraperitoneal injection. The blood samples were collected at different times for ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis. Changes of the pharmacokinetics parameters between the GXNI-treated and the blank control groups were used to evaluate the effects of GXNI on the four CYP450 isoforms in rats in vivo. After blood collection, the livers of rats were taken and made microsomes for in vitro tests. The relevant metabolites of phenacetin, tolbutamide, dextromethorphan and testosterone were analyzed quantitatively by high-performance liquid chromatography (HPLC) after microsome incubation. The statistical differences between the two groups were observed to detect the effects of GXNI on the four CYP450 isoforms in rats in vitro.

3. The in vivo and in vitro results demonstrated that GXNI could induce CYP1A2 activity in rats, but had no significant effects on CYP2C11, CYP2D1 and CYP3A1/2.     

In vitro study on the effect of peucedanol on the activity of cytochrome P450 enzymes

ContextPeucedanol is a major extract of Peucedanum japonicum Thunb. (Apiaceae) roots, which is a commonly used herb in paediatrics. Its interaction with cytochrome P450 enzymes (CYP450s) would lead to adverse effects or even failure of therapy.ObjectiveThe interaction between peucedanol and CYP450s was investigated.Materials and methodsPeucedanol (0, 2.5, 5, 10, 25, 50, and 100 μM) was incubated with eight human liver CYP isoforms (CYP1A2, 2A6, 3A4, 2C8, 2C9, 2C19, 2D6, and 2E1), in pooled human liver microsomes (HLMs) for 30 min with specific inhibitors as positive controls and untreated HLMs as negative controls. The enzyme kinetics and time-dependent study (0, 5, 10, 15, and 30 min) were performed to obtain corresponding parameters in vitro.ResultsPeucedanol significantly inhibited the activity of CYP1A2, 2D6, and 3A4 in a dose-dependent manner with IC₅₀ values of 6.03, 13.57, and 7.58 μM, respectively. Peucedanol served as a non-competitive inhibitor of CYP3A4 with a K_i value of 4.07 μM and a competitive inhibitor of CYP1A2 and 2D6 with a K_i values of 3.39 and 6.77 μM, respectively. Moreover, the inhibition of CYP3A4 was time-dependent with the K_i/K_inact value of 5.44/0.046 min/μM.Discussion and conclusionsIn vitro inhibitory effect of peucedanol on the activity of CYP1A2, 2A6, and 3A4 was reported in this study. As these CYPs are involved in the metabolism of various drugs, these results implied potential drug-drug interactions between peucedanol and drugs metabolized by CYP1A2, 2D6, and 3A4, which needs further in vivo validation.     

细胞色素P450(CYP450)遗传多态性研究进展

近年来对CYP450基因型和表型相关性的研究越来越受到重视,从临床合理用药方面来说,人们希望利用基因型分析来了解个体中药物代谢酶的活性,期望既能提高药物治疗水平同时又降低不良反应的发生;从新药研发角度来说,研究药物的代谢酶CYP450的功能能够指导新药的设计、筛选及优化。该文通过查阅国内外相关文献综述了近年来关于CYP450遗传多态性研究的进展,分别介绍了CYP2C19、CYP2C9、CYP3A4、CYP2D6、CYP1A2和CYP2E1这6种主要的药物代谢酶。研究CYP450对新药设计、筛选、评价及优化有重要意义。     

Effects of phillyrin and forsythoside A on rat cytochrome P450 activities in vivo and in vitro

1. Phillyrin and forsythoside A are two important active ingredients in Forsythia suspensa. However, the effects of phillyrin and forsythoside A on the activities of cytochrome P450 (CYP450) remain unclear.

2. This study aimed to investigate the effects of phillyrin and forsythoside A on the activities of CYP1A2, CYP2C11, CYP2D1 and CYP3A1/2 by cocktail probe drugs in rats both in vivo and in vitro.

3. Many pharmacokinetic parameters of caffeine and metoprolol in phillyrin pretreatment group, caffeine and tolbutamide in forsythoside A pretreatment group were affected significantly. In rat liver microsomal incubation system, the concentrations of acetaminophen and dextrophan in the phillyrin pretreatment group are higher than blank control group by 207.69% and 125.00%, however, the concentrations of 4-hydroxytolbutamide and 6β-hydroxytestosterone were not significantly altered. The concentrations of acetaminophen and 4-hydroxytolbutamide in the forsythoside A pretreatment group are higher than blank control group by 223.07% and 154.16%, whereas the concentrations of dextrophan and 6β-hydroxytestosterone were not significantly altered.

4. These results indicated that Phillyrin had potential inductive effects on rat CYP1A2 and CYP2D1 activities, without affecting CYP2C11 and CYP3A1/2 activities. Moreover, forsythoside A had inductive effects on the activities of CYP1A2 and CYP2C11, without affecting CYP2D1 and CYP3A1/2 activities.     

临床治疗剂量氯氮平人体内代谢机制研究

目的本课题主要探讨临床治疗剂量氯氮平的代谢机制，为临床合理用药提供指导。方法15例精神分裂症男性住院病人，单用氯氮平治疗，达到稳态浓度后，采用自身前后对照设计试验，研究氟西汀抑制前后氯氮平及其代谢产物药代动力学参数的变化及其与酶活性的相关性。CYP1A2、CYP3A4和CYP2136的活性分别用咖啡因、咪达唑仑和右美沙芬探测。体内氯氮平及其代谢产物、咪哒唑仑及其代谢产物、尿中右美沙芬及其代谢产物用HPLC-MS测定。血中咖啡因及其代谢产物用HPlC-UV测定。数据用SPSS软件进行统计分析。结果氯氮平合用氟西汀后，氯氮平的Cmax、AUC0-24显著增加，t1/2增加趋势，但没有显著性差异。代谢产物去甲氯氮平的AUC0-24显著降低，Cmax和t1／2无显著性差异。N-氧化氯氮平的Cmax和AUC0-24显著性降低，t1／2没有显著性差异。合用氟西汀前后CYP1A2活性无差异，CYP3A4和CYP2D6活性显著降低。合用氟西汀前后CYP1A2活性分别与合用氟西汀前后氯氮平的AUC0-24以及去甲氯氮平的AUC0-24相关，与N-氧化氯氮平的AUC0-24无显著相关。CYP3A4和CYP2D6活性与氯氮平、去甲氯氮平、N-氧化氯氮平的AUC0-24均无显著相关，但是合用氟西汀后CYP3A4活性变化与N-氧化氯氮平的AUC0-24变化显著相关，CYP2D6活性变化与去甲氯氮平的AUC0-24变化显著相关。结论临床剂量氯氮平的代谢途径为去甲基化和N-氧化，其中去甲基代谢为主要代谢途径主要由CYP1A2催化。CYP3A4和CYP2D6不是催化CLZ代谢的主要酶，但是CYP3A4参与了CLZN-氧化代谢，CYP2D6参与去甲基代谢。     

Pharmacokinetics of omeprazole in rats with dextran sulfate sodium–induced ulcerative colitis

Omeprazole is a commonly used drug in patients with ulcerative colitis (UC). This study investigated the pharmacokinetics of omeprazole in rats with UC induced by dextran sulfate sodium (DSS). The pharmacokinetics of intravenously administered omeprazole (20 mg/kg) was investigated in normal and UC rats using LC-MS/MS. The formation of 5-OH omeprazole, a main metabolite of omeprazole, in rat liver microsomes (RLMs) from normal and UC rats was compared. The protein levels of CYP1A2, CYP2D1, and CYP3A1 in the liver were measured by Western blot. Compared with normal rats, UC rats had increased plasma concentrations of omeprazole, resulting in an increased AUC_0–240 min and decreased CL. DSS treatment decreased the formation rate of 5-OH omeprazole in RLMs but did not change the affinity of the enzymes. The V_max and CL_int of RLMs from UC rats were 62% and 48% those of RLMs from normal rats, respectively. The hepatic CYP1A2 and CYP3A1 protein levels in UC rats were 42.6 and 45.2% lower than those in normal rats, respectively; however, the protein levels of CYP2D1 in the two groups were similar. The activity and expression of some hepatic CYP450 isoforms were decreased by UC, leading to changes in the pharmacokinetics of omeprazole.