丹红注射液对大鼠肝微粒体5种CYP亚型酶活性的影响

摘要目的研究丹红注射液对5种细胞色素P450亚型酶活性的影响,为临床合理用药提供参考。方法采用大鼠体外肝微粒体孵育法,分别以非那西丁、甲苯磺丁脲、右美沙芬、氯唑沙宗、睾酮为CYP1A2、CYP2C9、CYP2D6、CYP2E1、CYP3A4的探针药物,在大鼠肝微粒体孵育体系中孵育,用高效液相色谱（HPLC）法测定相应的代谢产物,比较空白对照组和丹红注射液低、中、高剂量组之间探针药物代谢率的差异,评价丹红注射液对各亚型酶活性的影响。结果在体外肝微粒体孵育体系中,丹红注射液低剂量组中CYP1A2 和CYP2C9活性与空白对照组相比,差异无统计学意义（P＞0.05）;中和高剂量组中CYP1A2和CYP2C9活性与空白对照组相比降低,差异有统计学意义（P＜0.05或P＜0.01）;丹红注射液低、中、高剂量组中CYP2D6、CYP2E1、CYP3A4的活性与空白对照组相比,差异无统计学意义（P＞0.05）。丹红注射液对大鼠肝微粒体CYP1A2酶活性的半数抑制浓度（IC50）和抑制常数（Ki）分别为0.54%和0.226%。结论丹红注射液对大鼠肝微粒体CYP1A2酶活性有抑制作用,且为混合型抑制;对CYP2C9有弱抑制作用;对CYP2D6、CYP2E1、CYP3A4酶活性无明显影响。     

灯盏细辛注射液对大鼠肝微粒体CYP3A的抑制作用

目的：研究灯盏细辛注射液对大鼠肝微粒体CYP3A酶活性的抑制作用。方法：在体外大鼠肝微粒体孵育体系中加入底物睾酮和不同体积的灯盏细辛注射液,用高效液相色谱法测定睾酮的羟化代谢产物6β-羟基睾酮的生成量反映CYP3A酶的活性。酮康唑用作阳性对照药。结果：在体外孵育体系中,灯盏细辛注射液对大鼠肝微粒体CYP3A酶活性有抑制作用,IC50和Ki值分别为0.40%和0.24%（V/V）。结论：体外给药灯盏细辛注射液对大鼠肝微粒体CYP3A酶活性有抑制作用,符合混合型抑制模型。     

灯盏花素注射液对大鼠体外肝微粒体细胞色素P450酶活性的影响

摘 要 目的:研究灯盏花素注射液对大鼠肝微粒体CYP1A2、CYP2C9、CYP2D6、CYP2E1和CYP3A1/2 五个亚型酶活性的影响。方法: 采用大鼠肝微粒体体外孵育法,选用非那西丁（CYP1A2）、甲苯磺丁脲（CYP2C9）、右美沙芬（CYP2D6）、氯唑沙宗（CYP2E1）和睾酮（CYP3A1/2）作为5个亚型酶的探针药物,孵育系统中加入不同浓度的灯盏花素注射液,用HPLC法测定5个亚型酶探针药物代谢产物的生成量,比较空白对照组与不同浓度灯盏花素注射液给药组探针药物的活性,反映灯盏花素注射液对5个亚型酶活性的影响。结果:大鼠肝微粒体体外孵育系统中,灯盏花素注射液对大鼠CYP3A1/2的IC₅₀为29.40μg·ml^-1,K_i为37.78 μg·ml^-1;对CYP1A2、CYP2C9、CYP2D6和CYP2E1的IC₅₀＞200 μg·ml^-1。结论:灯盏花素注射液对大鼠体外肝微粒体CYP3A1/2有弱的抑制作用,对CYP1A2、CYP2C9、CYP2D6和CYP2E1活性无明显影响。     

苦碟子注射液对大鼠肝微粒体CYP450酶5个亚型的体外抑制作用

目的研究苦碟子注射液对大鼠肝微粒体CYP450酶的体外抑制作用。方法制备大鼠肝微粒体。将苦碟子注射液分别与混合探针药物非那西丁、甲苯磺丁脲、奥美拉唑、睾酮和氯唑沙宗共同孵育,UPLC-MS/MS法检测各探针药物的代谢物。结果在测定浓度范围内,苦碟子注射液对CYP2E1、CYP2C9和CYP2C19的活性抑制率小于50%;对CYP1A2、CYP3A4的IC_(50)值分别为12.68%、8.11%,远高于临床日用药浓度0.20%~0.80%。结论在正常剂量下,苦碟子注射液对大鼠CYP2E1、CYP2C9、CYP2C19几乎不显示抑制作用,对CYP1A2、CYP3A4几乎没有抑制作用。     

脉络宁注射液对小鼠肝药酶活性的影响

目的：通过测定细胞色素P450（CYP450）含量和甲醛生成率,考察脉络宁注射液对小鼠总CYP450以及红霉素-N-脱甲基酶（CYP3A）和氨基比林-N-脱甲基酶（CYP2E1）活性的影响。方法：采用紫外分光光度法和体外温孵反应,测定并比较了给药组和对照组小鼠在肝脏系数、微粒体蛋白含量、CYP450含量及甲醛生成速率方面的差异。结果：两种剂量脉络宁对小鼠肝脏系数和CYP450含量影响都不显著,但均能提高微粒体蛋白含量;两种剂量脉络宁均可抑制CYP2E1的活性,临床等效用量时对CYP3A活性影响不显著,高剂量时可能抑制CYP3A活性。结论：脉络宁注射液对CYP3A和CYP2E1亚型活性有影响。     

淫羊藿苷对小鼠肝微粒体细胞色素P450酶及其亚型CYP2E1活性的影响

目的 研究淫羊藿苷对小鼠肝脏微粒体细胞色素P450(CYP)总酶含量及其亚型CYP2E1、CYP3A和CYP1A1活性的影响.方法 给予小鼠ig淫羊藿苷(50、100、200 mg·kg-1·d-1),3d后钙沉淀法制备肝细胞微粒体,UV法测定肝微粒体CYP的含量及其亚型CYP2E1与CYP3A的活性;荧光分光光度法测定肝微粒体CYP1A1的活性.结果 高剂量淫羊藿苷可降低小鼠肝脏微粒体CYP的含量(约54%)、抑制CYP2E1的活性(抑制率为53.1%),对CYP3A和CYP1A1的活性无影响.结论 大剂量淫羊藿苷可降低小鼠肝脏微粒体CYP的总含量,并抑制其亚型CYP2E1的活性.     

醒脑静注射液对人肝微粒体P450酶5种亚型体外抑制作用

目的研究醒脑静注射液对人肝微粒体P450酶5种亚型的体外抑制作用,以预测其潜在的代谢性药物相互作用。方法人肝微粒体、醒脑静注射液与5种探针底物奥美拉唑、右美沙芬、睾酮、氯唑沙宗和甲苯磺丁脲在烟酰胺腺嘌呤二核苷酸磷酸还原酶的作用下,于37℃水浴下共同孵育。通过液相色谱-质谱分析方法,测定探针底物的代谢产物生成量,评价醒脑静注射液对这5种酶亚型活性的影响。结果在人肝微粒体体外孵育反应体系中,醒脑静注射液对CYP2C19有较强的抑制作用,其IC_(50)值为0.36%;而对CYP2D6、CYP3A4、CYP2E1和CYP2C9的抑制作用相对较弱,其IC_(50)值为分别为7.37%、3.62%、2.50%和7.03%。结论醒脑静注射液可抑制CYP2C19酶亚型的活性,在临床使用过程中应注意潜在的代谢性药物相互作用。     

吴茱萸水煎液对大、小鼠肝药酶亚型影响的比较研究

目的比较吴茱萸水煎液对大鼠、小鼠肝药酶亚型的影响。方法取KM小鼠随机分为吴茱萸高剂量组(56 mg生药·g-1)、低剂量组(28 mg生药·g-1)和正常组,另取Wistar大鼠随机分为吴茱萸高剂量组(40 mg生药·g-1)、低剂量组(20 mg生药·g-1)和正常组,连续灌胃给予吴茱萸水煎液或等容量蒸馏水21 d后,采用药物探针法测定动物肝药酶亚型CYP1A、CYP2C、CYP2D、CYP2E1、CYP3A的活性。结果①小鼠实验结果显示,与正常组比较,吴茱萸高、低剂量组均诱导肝药酶亚型CYP1A、CYP2E1和CYP3A的活性(P<0.01),低剂量组诱导CYP2C活性(P<0.05);吴茱萸高、低剂量组对CYP2D活性无明显影响。②大鼠实验结果显示,与正常组比较,吴茱萸高、低剂量组均诱导肝药酶亚型CYP1A活性(P<0.01)。高剂量组诱导CYP2C和CYP2E1活性(P<0.05或0.01);吴茱萸高、低剂量组对CYP3A活性无明显影响;吴茱萸高、低剂量组均抑制CYP2D活性(P<0.01)。③实验结果对比显示,吴茱萸水煎液对大、小鼠肝药酶亚型的影响相同点是诱导了CYP1A、CYP2C及CYP2E1活性,尤其对CYP1A活性诱导更为明显。不同点是吴茱萸诱导了小鼠CYP3A活性,而对大鼠CYP3A活性无明显影响;吴茱萸对小鼠CYP2D活性无明显影响,而对大鼠CYP2D活性有明显抑制作用。结论吴茱萸水煎液对大、小鼠部分肝药酶亚型活性的影响有一定的差异性。     

头花蓼水提取物对CYP450酶诱导和抑制作用研究

目的考察头花蓼水提取物对人肝微粒体CYP450 5种亚型酶的体外抑制作用和对小鼠的体内诱导作用,从而预测发生药物相互作用的可能性,为临床合理用药提供科学依据。方法以探针底物代谢物生成法,考察头花蓼水提取物体外对人肝微粒体主要I相代谢酶CYP1A2、CYP2E1、CYP2C9、CYP2C19和CYP3A4活性的影响;采用微粒体体外孵育法,考察小鼠经高、低剂量(1.16、0.58 g·kg-1)头花蓼水提取物分别连续灌胃7 d和14 d后,小鼠肝微粒体中主要I相代谢酶活性的变化,以评价头花蓼水提取物对小鼠肝微粒体主要CYP450酶是否有诱导作用。结果头花蓼水提取物对人肝微粒体中主要的CYP450 I相代谢酶的抑制作用均不强,IC50值在849.6~2 287 mg·L-1;与空白对照组比较,1.16 g·kg-17 d组小鼠CYP2C9和CYP3A4活性分别增加了49.9%和21.1%(P<0.01和P<0.05),0.58 g·kg-114 d组小鼠CYP2C9和CYP3A4活性分别增加了27.6%和15.5%(P<0.01和P<0.05),1.16 g·kg-114 d组小鼠CYP2C9和CYP3A4活性分别增加了67.5%和32.1%(P<0.01),头花蓼提取物对其余CYP亚型活性未见明显影响。结论在临床剂量下,头花蓼水提取物对人肝微粒体CYP1A2、CYP2E1、CYP2C9、CYP2C19和CYP3A4无明显抑制作用,对小鼠肝微粒体CYP2C9和CYP3A4显示诱导作用。     

海藻–昆布药对对大鼠肝微粒体代谢酶的影响及肝毒性研究

目的发现不同剂量海藻–昆布药对提取物对大鼠肝微粒体代谢酶的诱导或抑制作用,预测服用海藻–昆布药对时可能出现的药物–药物相互作用及肝脏毒性。方法雌雄各半SD大鼠18只,被随机分为海藻–昆布药对低、高剂量组和对照组,低、高剂量组大鼠分别ig给予海藻–昆布药对提取物10.8、86.4 g/(kg·d),连续经口给药15 d后麻醉处死,取肝组织制备肝微粒体及HE染色石蜡切片。通过肝微粒体体外孵育方法测定3种肝脏CYP450同工酶特异性底物非那西丁(CYP1A2)、氯唑沙宗(CYP2E1)及咪达唑仑(CYP3A4)的降解和代谢产物生成量来评价肝药酶的诱导或抑制作用,并以光镜下的组织病理切片检查来考察其肝毒性。结果低剂量组大鼠无显著诱导或抑制3种CYP450代谢酶亚型1A2、2E1和3A4现象,肝组织出现了肝窦扩张、轻度水肿等适应性改变,高剂量组能显著诱导CYP3A4亚型,但也不能显著的诱导或抑制肝微粒体代谢酶CYP1A2、CYP2E1亚型,肝组织出现了脂肪变、点状坏死等可逆性损伤。结论海藻–昆布药对具有诱导肝微粒体代谢酶CYP3A4的作用和轻微的肝细胞毒性,高剂量经口给药能引起有临床意义的CYP450酶的诱导现象和肝脏损伤并可能导致不期望的药物–药物相互作用。     

In vitro evaluation of valproic acid as an inhibitor of human cytochrome P450 isoforms: preferential inhibition of cytochrome P450 2C9 (CYP2C9)

AIMS: To evaluate the potency and specificity of valproic acid as an inhibitor of the activity of different human CYP isoforms in liver microsomes. METHODS: Using pooled human liver microsomes, the effects of valproic acid on seven CYP isoform specific marker reactions were measured: phenacetin O-deethylase (CYP1A2), coumarin 7-hydroxylase (CYP2A6), tolbutamide hydroxylase (CYP2C9), S-mephenytoin 4'-hydroxylase (CYP2C19), dextromethorphan O-demethylase (CYP2D6), chlorzoxazone 6-hydroxylase (CYP2E1) and midazolam 1'-hydroxylase (CYP3A4). RESULTS: Valproic acid competitively inhibited CYP2C9 activity with a Ki value of 600 microM. In addition, valproic acid slightly inhibited CYP2C19 activity (Ki = 8553 microM, mixed inhibition) and CYP3A4 activity (Ki = 7975 microM, competitive inhibition). The inhibition of CYP2A6 activity by valproic acid was time-, concentration- and NADPH-dependent (KI = 9150 microM, Kinact=0.048 min(-1)), consistent with mechanism-based inhibition of CYP2A6. However, minimal inhibition of CYP1A2, CYP2D6 and CYP2E1 activities was observed. CONCLUSIONS: Valproic acid inhibits the activity of CYP2C9 at clinically relevant concentrations in human liver microsomes. Inhibition of CYP2C9 can explain some of the effects of valproic acid on the pharmacokinetics of other drugs, such as phenytoin. Co-administration of high doses of valproic acid with drugs that are primarily metabolized by CYP2C9 may result in significant drug interactions.     

Effects of serum albumin and liver cytosol on CYP2C9- and CYP3A4-mediated drug metabolism

To investigate whether the free-drug theory is accurate in that only unbound drug is available for drug metabolism or enzyme inhibition. The effect of addition of rat liver cytosol to an in vitro system using human liver microsomes was examined by measuring the catalytic activities of CYP2C9 (tolbutamide and diclofenac) and CYP3A4 (terfenadine). And, the results were compared with those obtained when human serum albumin (HSA) was added to microsomes as far as unbound drug concentrations were concerned. After addition of rat liver cytosol, the unbound Km value (Km,u) for terfenadine metabolism by CYP3A4, and the unbound Ki value of miconazole (Ki,u) for CYP2C9 were smaller than for the controls. Addition of HSA resulted in smaller Km,u values for diclofenac and terfenadine metabolism by CYP2C9 and CYP3A4, respectively, and the Ki,u value for ketoconazole inhibition of CYP3A4 was also reduced. These results suggest protein-facilitated effects on drug metabolism and enzyme inhibition for both CYP2C9 and CYP3A4. However, no protein-facilitated drug metabolism was observed for tolbutamide in the presence of HSA or cytosol, or for diclofenac in the presence of cytosol. Protein-facilitated enzyme inhibition did not occur with miconazole in the presence of HSA or with ketoconazole in the presence of rat liver cytosol. Protein-facilitated metabolism and enzyme inhibition were observed for CYP2C9 and CYP3A4 in five cases but there was no obvious pattern of enzyme, substrate, or binding protein specificity. Further investigations are necessary to clarify the relevance of these results to in vivo observations.     

Direct effects of neuroleptics on the activity of CYP2A in the liver of rats

The aim of the present study was to investigate the influence of classic and atypical neuroleptics on the activity of rat CYP2A measured as a rate of testosterone 7alpha-hydroxylation. The reaction was studied in control liver microsomes in the presence of neuroleptics, as well as in microsomes of rats treated intraperitoneally (i.p.) for one day or two weeks (twice a day) with pharmacological doses (mg/kg) of the drugs (promazine, levomepromazine, thioridazine, perazine 10, chlorpromazine, haloperidol 0.3, risperidone 0.1, sertindole 0.05), in the absence of the neuroleptics in vitro. Most of the neuroleptics added in vitro to control liver microsomes decreased the activity of the rat CYP2A. Chlorpromazine (Ki = 11 microM) was the most potent inhibitor of the rat CYP2A among the studied drugs, whose effect was more pronounced than that of the other tested phenothiazines (Ki = 41-83 microM), haloperidol (Ki = 190 microM) or sertindole (Ki = 78 microM). Risperidone was not active in this respect. The investigated neuroleptics when given to rats in vivo for one day or two weeks--did not produce any indirect inhibitory effect on CYP2A via other mechanisms. The obtained results show direct inhibitory effects of phenothiazine neuroleptics on the activity of CYP2A in rat liver, which may be of physiological importance for the metabolism of testosterone, considering simultaneous inhibition of CYP2C11 and CYP3A by those drugs.     

Inhibition of rat liver CYP2D in vitro and after 1-day and long-term exposure to neuroleptics in vivo-possible involvement of different mechanisms.

The aim of the present study was to investigate the influence of classic and atypical neuroleptics on the activity of rat CYP2D measured as a rate of ethylmorphine O-deethylation. The reaction was studied in control liver microsomes in the presence of neuroleptics, as well as in microsomes of rats treated intraperitoneally (i.p.) for 1-day or 2-weeks (twice a day) with pharmacological doses of the drugs (promazine, levomepromazine, thioridazine, perazine 10 mg kg(-1); chlorpromazine 3 mg kg(-1); haloperidol 0.3 mg kg(-1); risperidone 0.1 mg kg(-1); sertindole 0.05 mg kg(-1)), in the absence of the neuroleptics in vitro. Neuroleptics added in vitro to control liver microsomes decreased the activity of the rat CYP2D by competitive or mixed inhibition of the enzyme. Thioridazine (Ki=15 microM) was the most potent inhibitor of the rat CYP2D among the drugs studied, whose effect was more pronounced than that of the other neuroleptics tested: phenothiazines (Ki=18-23 microM), haloperidol (Ki=32 microM), sertindole (Ki=51 microM) or risperidone (Ki=165 microM). The investigated neuroleptics-when given to rats in vivo-also seemed to exert an inhibitory effect on CYP2D via other mechanisms. One-day exposure of rats to the classic neuroleptics decreased the activity of CYP2D in rat liver microsomes. After chronic treatment with the investigated neuroleptics, the decreased CYP2D activity produced by the phenothiazines was still maintained, while that caused by haloperidol diminished. Moreover, risperidone decreased the activity of that enzyme. The obtained results indicate drug- and time-dependent interactions between the investigated neuroleptics and the CYP2D subfamily of rat cytochrome P-450, which may proceed via different mechanisms: (1) competitive or mixed inhibition of CYP2D shown in vitro, the inhibitory effects of phenothiazines being stronger than those of haloperidol or atypical neuroleptics, but weaker than the effects of the respective drugs on human CYP2D6; (2) in vivo inhibition of CYP2D, produced by both 1-day and chronic treatment with phenothiazines, which suggests inactivation of enzyme by intermediate metabolites; (3) in vivo inhibition of CYP2D by risperidone, produced only by chronic treatment with the drug, which suggests its influence on the enzyme regulation.     

Effects of phenothiazine neuroleptics on the rate of caffeine demethylation and hydroxylation in the rat liver

The primary metabolic pathways of caffeine are 3-N-demethylation to paraxanthine (CYP1A2), 1-N-demethylation to theobromine and 7-N-demethylation to theophylline (CYP1A2 and other enzymes), and 8-hydroxylation to 1,3,7-trimethyluric acid (CYP3A). The aim of the present study was to investigate the influence of phenothiazine neuroleptics (chlorpromazine, levomepromazine, thioridazine, perazine) on cytochrome P-450 activity measured by caffeine oxidation in rat liver microsomes. The obtained results showed that all the investigated neuroleptics competitively inhibited caffeine oxidation in the rat liver, though their potency to inhibit particular metabolic pathways was not equal. Levomepromazine exerted the most potent inhibitory effect on caffeine oxidation pathways, the effect on 8-hydroxylation being the most pronounced. This indicates inhibition of CYP 1 A2 (inhibition of 3-N- and 1-N-demethylation; Ki = 36 and 32 microM, respectively), CYP3A2 (inhibition of 8-hydroxylations; Ki = 20 microM), and possibly other CYP isoenzymes (inhibition of 7-N-demethylation; Ki = 58 microM) by the neuroleptics. The potency of inhibition of caffeine oxidation by perazine was similar to levomepromazine. Thioridazine was a weaker inhibitor of caffeine 3-N- and 7-N-demethylation, while chlorpromazine was weaker in inhibiting caffeine 1-N- and 7-N-demethylation, compared to levomepromazine. In summary, the obtained results showed that all the investigated neuroleptics had a broad spectra of CYP inhibition in the rat liver. The isoenzymes CYP1A2 and CYP3A2 were distinctly inhibited by all the investigated neuroleptics, while other CYP isoenzymes (CYP2B and/or 2E1) by perazine and levomepromazine. The CYP3A2 inhibition was most pronounced. (Ki = 20-40 microM).     

新型Hsp90抑制剂——SNX-2112对大鼠肝药酶活性的影响

目的研究SNX-2112注射液对大鼠肝药酶活性的影响。方法大鼠分为苯巴比妥钠诱导组、CCl4抑制组、SNX-2112高、中、低(10、5、2.5mg·kg-1)剂量组、生理盐水对照组、空白溶媒组。用紫外分光光度法测定了SNX-2112注射液对大鼠肝脏系数、CYP450含量以及甲醛生成速率的影响。结果3种剂量SNX-2112对大鼠肝脏系数以及蛋白含量的影响都不明显,但均能抑制CYP450含量。从甲醛生成速率结果看,高、中两种剂量SNX-2112均能抑制大鼠氨基比林-N-脱甲基酶活性及红霉素-N-脱甲基酶活性,而低剂量对其影响不明显。结论SNX-2112注射液在高浓度对大鼠肝药酶CYP3A和CYP2E1亚型活性有抑制作用。     

Inhibitory effects of silibinin on cytochrome P-450 enzymes in human liver microsomes

Silibinin, the main constituent of silymarin, a flavonoid drug from silybum marianum used in liver disease, was tested for inhibition of human cytochrome P-450 enzymes. Metabolic activities were determined in liver microsomes from two donors using selective substrates. With each substrate, incubations were carried out with and without silibinin (concentrations 3.7-300 microM) at 37 degrees in 0.1 M KH2PO4 buffer containing up to 3% DMSO. Metabolite concentrations were determined by HPLC or direct spectroscopy. First, silibinin IC50 values were determined for each substrate at respective K(M) concentrations. Silibinin had little effect (IC50>200 microM) on the metabolism of erythromycin (CYP3A4), chlorzoxazone (CYP2E1), S(+)-mephenytoin (CYP2C19), caffeine (CYP1A2) or coumarin (CYP2A6). A moderate effect was observed for high affinity dextromethorphan metabolism (CYP2D6) in one of the microsomes samples tested only (IC50=173 microM). Clear inhibition was found for denitronifedipine oxidation (CYP3A4; IC50=29 microM and 46 microM) and S(-)-warfarin 7-hydroxylation (CYP2C9; IC50=43 microM and 45 microM). When additional substrate concentrations were tested to assess enzyme kinetics, silibinin was a potent competitive inhibitor of dextromethorphan metabolism at the low affinity site, which is not CYP2D6 (Ki.c=2.3 microM and 2.4 microM). Inhibition was competitive for S(-)-warfarin 7-hydroxylation (Ki,c=18 microM and 19 microM) and mainly non-competitive for denitronifedipine oxidation (Ki,n=9 microM and 12 microM). With therapeutic silibinin peak plasma concentrations of 0.6 microM and biliary concentrations up to 200 microM, metabolic interactions with xenobiotics metabolised by CYP3A4 or CYP2C9 cannot be excluded.     

刺五加注射液对大鼠肝CYP3A活性的影响

目的:考察刺五加注射液对大鼠肝细胞色素P4503A活性的影响。方法:制备大鼠空白肝微粒体,加入刺五加注射液孵育,HPLC法测定咪达唑仑浓度,计算咪达唑仑代谢速率评价刺五加注射液体外对大鼠CYP3A酶的影响。大鼠随机分为对照组和实验组,分别尾静脉注射生理盐水和刺五加注射液,连续7 d,制备肝微粒体,进行孵育反应,评价刺五加注射液体内对大鼠CYP3A的影响。结果:刺五加注射液体外对大鼠CYP3A酶具有抑制作用,测得刺五加注射液抑制CYP3A酶的IC50为5.00 mL/100mL。大鼠连续7 d静脉注射刺五加注射液,使探针药物咪达唑仑的代谢减少了21.11%。结论:刺五加注射液对大鼠CYP3A的活性有抑制作用。     

Interactions between neuroleptics and CYP2C6 in rat liver--in vitro and ex vivo study

The aim of the present study was to investigate the influence of classic and atypical neuroleptics on the activity of rat CYP2C6 measured as a rate of warfarin 7-hydroxylation. The reaction was studied in control liver microsomes in the presence of neuroleptics, as well as in microsomes of rats treated intraperitoneally for one day or two weeks (twice a day) with pharmacological doses (mg/kg) of the drugs (promazine, levomepromazine, thioridazine, perazine 10, chlorpromazine, haloperidol 0.3, risperidone 0.1, sertindole 0.05), in the absence of the neuroleptics in vitro. Some of the neuroleptics added in vitro to control liver microsomes decreased the activity of CYP2C6. Sertindole and levomepromazine (Ki = 25 and 31 microM, respectively) were the most potent inhibitors of the rat CYP2C6 among the drugs studied. Their effects were more pronounced than those of the other phenothiazines tested: thioridazine and chlorpromazine (Ki = 88 and 91 microM, respectively), promazine and perazine (Ki = 322 and 341 microM, respectively), risperidone (Ki = 414 microM) or haloperidol (Ki = 606 microM). The investigated neuroleptics--when given to rats in vivo for one day or two weeks--did not produce any indirect effect on CYP2C6 via other mechanisms, except for levomepromazine, which increased the activity of the enzyme after 24-h exposure. Therefore, the direct inhibitory effect of levomepromazine on CYP2C6 may be attenuated by an indirect mechanism at the beginning of the neuroleptic therapy. In summary, the obtained results show direct inhibitory effects of some phenothiazine neuroleptics and sertindole on the activity of CYP2C6 in vitro in rat liver microsomes. Considering relatively high pharmacological doses and therapeutic concentrations of phenothiazines, it seems that the inhibitory effect of levomepromazine (and other phenothiazines with Ki values below 100 microM) found in vitro may be of physiological and pharmacological importance in vivo.