反相高效液相色谱法研究家兔体内利福定对地塞米松代谢动力学的影响

已知利福平是一种肝微粒体酶诱导剂,我们在临床药学工作中发现,与利福平结构相似的另一强效抗菌药利福定与糖皮质激素联用时,可使后者的临床疗效显著降低。因此,推测利福定也可能有肝微粒体酶诱导作用,从而加速糖皮质激素的肝脏代谢,降低其治疗有效浓度。本实验从药物相互作用的角度,研究家兔体内利福定对地塞米松代谢动力学的影响。     

利福喷丁和苯巴比妥诱导小鼠肝细胞滑面内质网增生的作用

利福喷丁是新型长效抗结核抗生素,通过透射电镜观察,发现它和典型的肝微粒体酶诱导剂苯巴比妥均能显著诱导小鼠肝细胞滑面内质网的增生。由于这种作用常与肝微粒体酶诱导作用有关,故本文从形态学方面证实了利福喷丁和苯巴比妥对肝微粒体酶具有诱导作用。     

DHDK肝微粒体代谢动力学研究

目的 研究抗肿瘤候选药物DHDK在人和大鼠肝微粒体的代谢动力学特征,比较种属差异,为临床前研究提供依据。方法 建立HPLC法测定DHDK在肝微粒体孵育体系中的含量,用于考察DHDK体外代谢稳定性和酶动力学,进而推算其在体内的肝清除率(CL_h)与肝提取率(ER)。结果 肝微粒体孵育试验表明DHDK在两个种属之间的体外代谢稳定性和酶动力学行为无显著性差异(P>0.05),但在人体内的肝清除率显著低于大鼠(P<0.05)。结论 DHDK体外代谢主要依赖于烟酰胺腺嘌呤二核苷酸磷酸和肝微粒体酶,属于中等程度代谢消除。     

环丙沙星对人肝微粒体药物酶活性的影响

目的：观察环丙沙星对人肝微粒体药物代谢酶活性的影响。方法：用正常人新鲜肝组织低温匀浆,低温超速离心分离肝微粒体,测定肝微粒体细胞色素P450（CP450）的含量。以环丙沙星为处理因素,作肝微粒体药物代谢活性测定的体外试验。反应体系中微粒体蛋白的终浓度为1．0g/L,环丙沙星的终浓度为400mg/L。结果：环丙沙星对人肝微粒体药物代谢酶的活性抑制有选择性,对不同酶其抑制强度不同。对多种酶的抑制强弱顺序为：戊巴比妥侧链羟化酶＞苯并芘羟化酶＞乙基吗啡N－脱甲基酶, 其抑制率分别为0．34、0．30、和0．18。结论：环丙沙星对人肝微粒体多种药物代谢酶活性有明显的抑制作用。提示对肝功异常者、使用戊巴比妥钠麻醉的病人、经常服用吗啡类药物及高苯比芘含量环境工作人员该类药物应慎用。     

辛伐他汀对大鼠肝微粒体药物代谢酶活性的影响

目的 研究辛伐他汀(simvastatin, SV)对大鼠肝脏药物代谢酶活性的影响。方法 大鼠口服给予SV,qd×7,超速离心法分离肝微粒体,一氧化碳示差光谱法测定细胞色素P450(CYP)含量,以红霉素、苯胺、CDNB、利尿酸、7-羟基-4-甲基香豆素和对羟基联苯为底物分别测定肝微粒体红霉素脱甲基酶(CYP3A4)、苯胺羟化酶(CYP2E1)、谷胱甘肽-S-转移酶(glutathione S transferase, GST)及其π亚型 (πGST)、尿苷二磷酸葡萄糖醛酸转移酶(uridine diphosphoglucuronyl transferase, UGT1和UGT2)活性。结果 大鼠口服给予SV可明显降低大鼠肝微粒体CYP含量及CYP3A4活性,对CYP2E1则没有显明影响。同时,SV 则可显著增高大鼠肝微粒体GST、πGST及UGT1和UGT2活性。结论 SV可降低大鼠肝微粒体CYP3A4活性,而增高肝微粒体Ⅱ相代谢酶的活性。     

利福喷丁对小鼠和大鼠肝微粒体酶的影响

<正> 利福喷丁(rifapentine,R773)是我国近年研制的新型长效利福霉素。国内外曾报道利福平在人体内能加速自身及其他若干种药物的代谢。作为同类衍生物,利福喷丁可能也具有肝微粒体酶诱导作用,本文报道了这方面的动物实验结果。 利福喷丁处理对小鼠肝重的影响 昆明小鼠?,体重18±SD2g,随机分为4组,每组10只,对照组每两天ig一次1％甲基纤维素溶液(R773的溶剂)0.2ml/只;其余3组分别igR773 10,20和40mg/kg,隔日一次,共给药15d。结果各组小鼠的相对肝脏重量(肝重占体重的百分比)依次为:对照组4.8±SD0.4％;R77310mg/kg组5.5±0.4％;     

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。     

米氮平在鼠肝微粒体中的体外代谢研究

目的:通过不同诱导剂预处理鼠肝,研究米氮平在肝微粒体中的代谢主要受何种酶影响,同时研究米氮平对介导其自身代谢的P450酶亚型是否有影响,为米氮平的临床合理应用提供科学依据。方法:将米氮平与不同诱导剂诱导的鼠肝微粒体进行体外孵育代谢,以乙腈中止反应,样品用25%氨水碱化后以环己烷提取。用RPHPLC测定剩余的米氮平含量,流动相为甲醇水(含10mmol·L-1NH4AC,5mmol·L-1SDS,pH3.5)6238(VV),检测波长为307nm。结果:本文测定方法回收率高,日内和日间精密度均良好,符合生物样本检测要求。苯巴比妥诱导的鼠肝微粒体对米氮平的代谢具有明显的催化作用,利福平也有一定的催化能力,米氮平诱导的鼠肝微粒体与对照组对米氮平的代谢无明显差异。结论:由苯巴比妥诱导的P450酶亚型(主要为细胞色素P4503A4)和利福平诱导的P450酶亚型(主要为细胞色素P4502C92C19,同时也对P4503A4有一定的诱导作用)在米氮平的体外代谢中起着重要作用;而米氮平诱导组对于米氮平代谢无明显影响,预示米氮平对介导其自身代谢的P450酶亚型无明显的诱导或抑制作用。     

硒多糖、亚砷酸钠对大鼠肝微粒体酶和GSH-Px等的影响

研究了硒多糖、亚砷酸钠在体内、外对大鼠肝微粒体酶细胞色素Ｐ－４５０、ｂ５、ＮＡＤ（Ｐ）Ｈ－细胞色素Ｃ还原酶、谷胱甘肽硫转移酶（ＧＳＴ）的影响;并通过测定硒多糖、亚砷酸钠对肝谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）和脂质过氧化（ＬＰＯ）的影响,探讨了硒、砷相互作用的机理。结果表明：连续７天腹腔注射０．２ｍｇ／ｋｇ硒多糖,细胞色素Ｐ－４５０、ｂ５的含量、ＧＳＴ的活性降低（Ｐ＜０．０５）;硒多糖明显诱导ＧＳＨ－Ｐｘ的活性,降低脂质过氧化,拮抗亚砷酸钠对ＬＰＯ的作用。亚砷酸钠显著增强肝细胞脂质过氧化（Ｐ＜０．０５）,对ＧＳＨ－Ｐｘ和肝微粒体酶无明显影响     

大黄酸对大鼠肝细胞色素P4503A酶活性的抑制

（1. ［摘要］目的研究大黄酸对大鼠肝微粒体细胞色素P450 3A（CYP3A）酶活性的影响。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浓度的大黄酸,采用高效液相色谱仪测定睾酮的羟基化代谢产物6β羟基睾酮的含量,计算CYP3A酶活性来反映大黄酸对CYP3A酶的抑制效果。结果大鼠肝微粒体孵育体系中,大黄酸对CYP3A酶活性有抑制作用,其半数抑制浓度（IC50）和Ki值分别为36.74,20.73 μmol&#8226;L 1。结论在大鼠肝微粒体体外孵育系统中,大黄酸对CYP3A酶具有抑制作用。     

Inductive effects of rifapentine on mice hepatic mixed function oxidase system

Rifapentine (R773, DL473) is a long-acting antituberculous drug used in China. In our experiments we have found some manifestations of induction of hepatic mixed function oxidase system in mice following pretreatment with rifapentine or phenobarbital. Both rifapentine and phenobarbital significantly increased the rate of antipyrine and pentobarbital metabolism in vivo. They also increased liver weight, the content of liver microsomal protein and cytochrome P-450, the activity of NADPH-cytochrome C reductase and NADPH oxidase. SDS-polyacylamide gel electrophoresis showed that the relative proportions of some polypeptide bands in mice microsomal fraction were significantly changed following rifapentine or phenobarbital pretreatment. The results indicate that rifapentine, like phenobarbital, is a potent inducer of hepatic mixed function oxidase system in mice and that it should be used carefully in clinical therapy, when combined with other drugs.     

Atypical inductive properties of rifampicin.

Hepatic and microsomal parameters, metabolism of cytochrome P-450-dependent substrates and spectral properties of cytochrome P-450 have been used in mice in order to classify rifampicin as an inducer by comparing it to phenobarbitone and 3-methylcholanthrene. Rifampicin significantly enhanced relative liver weight, cytochrome P-450 content, microsomal protein, weight of the 100,000 g pellet and shortened the zoxazolamine paralysis time. Compared on the basis of microsomal protein, of five substrate reactions only the ethylmorphine demethylation was enhanced; ethoxycoumarin deethylation and biphenyl 1–2-hydroxylation were unaltered; ethoxyresorufin de-ethylation and biphenyl-4-hydroxylation were decreased. The CO-cytochrome P-450 absorption maximum showed a blue shift of about 0.5 nm after only 1 day of rifampicin pretreatment, while there was no significant blue shift after 1 day of 3-methylcholanthrene pretreatment. Rifampicin has been shown to be an inducer in NMRI mice. Although resembling phenobarbitone it seems, however, to be a similarly atypical inducer as it is in man.     

利福平及异烟肼对家兔体内地西泮药代动力学的影响

用HPLC测定方法,研究了家兔多次ig利福平(100mg·kg^-1·d^-1×4)及异烟肼(50mg·kg^-1×4)后,对iv地西泮的药代动力学。结果表明,给药后利福平组肝微粒体细胞色素P-450含量增加98.1%,使地西泮的T_1/2β由98.77±19.38min减少到40.08±17.75min;AUC由143.52±41.41mg·min·L^-1减少到79.10±11.46mg·min·L^-1;CL由22.41±8.12ml·min^-1·kg^-1增加到43.96±10.38ml·kg^-1·min^-1。异烟肼组则表现出相反的作用。而利福平与异烟肼合用组对P-450含量及地西泮的动力学均无显著影响。提示利福平诱导家兔肝药酶的作用可加速地西泮的体内代谢过程,异烟肼抑制肝药酶减低地西泮的代谢。     

Regulation of renal cytochrome P-450. Effects of two-thirds hepatectomy, cholestasis, biliary cirrhosis and post-necrotic cirrhosis on hepatic and renal microsomal enzymes

The possibility of a relationship between hepatic and renal cytochrome P-450 contents was assessed in rats with liver disease. In rats killed 3 days after two-thirds hepatectomy (a model for hepatocellular insufficiency), the total microsomal cytochrome P-450 content of the whole liver was decreased by 60% as compared to that in control rats; renal cytochrome P-450 was increased by 30% while the 7-ethoxycoumarin deethylase activity of kidney microsomes was increased by 80%. In rats killed 7 days after bile duct ligation (a model for cholestasis) or 35 days after bile duct ligation (a model for biliary cirrhosis), hepatic cytochrome P-450 was decreased by 60% and 45%, respectively, while renal cytochrome P-450 content was increased by 50% and 150%, respectively. In contrast, in rats killed 15 days after the last dose of carbon tetrachloride, 1.3 ml/kg twice weekly for 3 months (a model for post-necrotic cirrhosis), both hepatic and renal cytochrome P-450 contents remained unchanged. Phenobarbital (80 mg/kg daily for 3 days) was a poor inducer of renal cytochrome P-450 in sham-operated rats but became a potent inducer of renal cytochrome P-450 in rats with two-thirds hepatectomy. We conclude that renal cytochrome P-450 is increased in three models in which hepatic cytochrome P-450 contents are decreased (two-thirds hepatectomy, cholestasis and biliary cirrhosis), but remains unchanged in a model of severe liver pathology, in which hepatic cytochrome P-450 content is not modified (late, post-necrotic cirrhosis). The hypothetical role of endogenous inducer(s) is discussed.     

Proliferation of peroxisomes and induction of cytosolic and microsomal epoxide hydrolases in different strains of mice and rats after dietary treatment with clofibrate

1. The effects of dietary clofibrate (0.5%, w/w, for 10 days) on seven inbred strains of mice--C57BL/6, C57BL/B10A(5R), ATL/OLA, C3H/HE/OLA, BALB/C, CBA/CA and A/J/OLA--and three strains of rats--Sprague-Dawley, Wistar and LOU/OLA--have been investigated. Liver weight, peroxisome proliferation, catalase activity, cytosolic, microsomal and mitochondrial epoxide hydrolase activities, cytochrome oxidase activity, microsomal cytochrome P-450 content and cytosolic glutathione transferase activity in liver were determined, together with cytosolic and microsomal epoxide hydrolase and cytosolic glutathione transferase activities in the kidneys. 2. In all cases peroxisome proliferation and induction of cytosolic epoxide hydrolase were observed in livers of rodents exposed to clofibrate. Thus, no non-responsive strains were found and further evidence for a coupling between these two phenomena was provided. In many cases significant increases in the liver microsomal cytochrome P-450 content and decreases in the hepatic cytosolic glutathione transferase activity were also seen. 3. High levels of cytosolic epoxide hydrolase were found in the rat kidney. In several strains of mice and rats renal cytosolic epoxide hydrolase activity was increased by clofibrate. 4. There were often considerable strain differences. However, in general mice had higher cytosolic epoxide hydrolase and glutathione transferase activities, whereas rats had higher microsomal epoxide hydrolase activities.     

Proliferation of peroxisomes and induction of cytosolic and microsomal epoxide hydrolases in different strains of mice and rats after dietary treatment with clofibrate

1. The effects of dietary clofibrate (0.5%, w/w, for 10 days) on seven inbred strains of mice—C57BL/6, C57BL/B10A(5R), ATL/OLA, C3H/HE/OLA, BALB/C, CBA/CA and A/J/OLA—and three strains of rats—Sprague-Dawley, Wistar and LOU/OLA—have been investigated. Liver weight, peroxisome proliferation, catalase activity, cytosolic, microsomal and mitochondrial epoxide hydrolase activities, cytochrome oxidase activity, microsomal cytochrome P-450 content and cytosolic glutathione transferase activity in liver were determined, together with cytosolic and microsomal epoxide hydrolase and cytosolic glutathione transferase activities in the kidneys.

2. In all cases peroxisome proliferation and induction of cytosolic epoxide hydrolase were observed in livers of rodents exposed to clofibrate. Thus, no non-responsive strains were found and further evidence for a coupling between these two phenomena was provided. In many cases significant increases in the liver microsomal cytochrome P-450 content and decreases in the hepatic cytosolic glutathione transferase activity were also seen.

3. High levels of cytosolic epoxide hydrolase were found in the rat kidney. In several strains of mice and rats renal cytosolic epoxide hydrolase activity was increased by clofibrate.

4. There were often considerable strain differences. However, in general mice had higher cytosolic epoxide hydrolase and glutathione transferase activities, whereas rats had higher microsomal epoxide hydrolase activities.     

Differential effects of aging on hepatic microsomal monooxygenase induction by phenobarbital and β-naphthoflavone

The influence of aging on hepatic microsomal monooxygenase induction by phenobarbital (PB) or β-naphthoflavone (BNF) was investigated in male Fischer 344 rats maintained in a constant environment. PB-induced increases in microsomal cytochrome P-450 content and NADPH-cytochrome c reductase activity were similar in rats aged 3–5 months (young-adult) and 24–25 months (old), but increases in benzephetamine N-demethylase activity were markedly diminished in the old rats. Separation of hepatic microsomal proteins by sodium dodecylsulfate gel electrophoresis demonstrated that aging decreased the induction by PB of a polypeptide with a molecular weight of 52,500. BNF-induced increases in microsomal cytochrome P-450 and nitroanisole O-demethylase activity were greater in old than in young-adult rats, and BNF induction of 55,000 and 57,000 molecular weight microsomal polypeptides was increased slightly in livers from old rats. The results indicate that age-related effects on monooxygenase induction vary with different inducers of the hepatic microsomal enzyme system.     

Induction of cytochrome P-450, cytochrome b-5, NADPH-cytochrome c reductase and change of cytochrome P-450 isozymes with long-term trichloroethylene treatment

Several reports have described the effects of trichloroethylene (TCE) on the microsomal mixed function oxidase system (MFOS). These studies suggest that repeated TCE administration induces MFOS, especially cytochrome P-450 and NADPH-cytochrome c reductase. However, it is uncertain what isozymes are induced by TCE treatment, and it is not clear how microsomal enzymes or cytochrome P-450 isozymes are altered when TCE is administered for a duration longer than 28 days. We investigated the changes of MFOS by long-term TCE treatment. Male Wistar rats were injected with TCE, 1.0 g/kg body weight once a day for 5 continuous days or 2.0 g/kg body weight twice a week for 15 days. The mean body weight of the rats treated with TCE for 15 weeks was slightly, but not significantly, less than that of the control rats. Relative liver weights (liver wt/body wt) of the TCE-treated group were however significantly larger (21%) than those of the control group. The weights of the other organs were not changed by long-term TCE treatment. Trichloroethylene treatments for 5 days and 15 weeks caused significant increases in microsomal protein, cytochrome P-450, cytochrome b-5 and NADPH-cytochrome c reductase. TCE treatments produced an increase in a polypeptide band at 52,000 molecular weight range observed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). This increase in similar to, but less pronounced than that induced by phenobarbital (PB) treatment. There were no remarkable changes at 56,000 molecular weight range where a band appeared after the treatment with 3-methylcholanthrene (MC). It is likely that the induction of cytochrome P-450 by TCE is relatively similar to that by PB.     

利福喷丁对小鼠肝微粒体药酶的诱导作用

连续给小鼠口服利福喷丁40mg/kg或20mg/kg14日后,用药鼠的戊巴比妥钠催眠时间显著缩短,利福喷丁血浓下降,鼠肝重增加,而SGPT活性无改变。鼠肝细胞中细胞色素P-450和细胞色素B_b含量明显增加,表明利福喷丁有诱导小鼠肝药酶的作用。     

Effect of synthetic estrogens and estrogen-progestin combinations on the hepatic microsomal enzyme system

Pretreatment of male rats with mestranol or ethynyl estradiol 10 min prior to the administration of pentobarbital had no effect on the duration of pentobarbital-induced sleep. Although the estrogens are alternate substrates for the microsomal enzyme system which metabolizes pentobarbital, the concentrations used in this study did not affect pentobarbital metabolism. Chronic pretreatment with mestranol or ethynyl estradiol did not induce the hepatic microsomal enzyme system, as determined by measuring the concentration of cytochrome P-450, the rate of activity of cytochrome P-450 reductase and the amount of microsomal protein/g of rat liver. However, chronic pretreatment with ethynyl estradiol or mestranol markedly decreased the daily body weight gain of the rats, but did not significantly alter the weight of their livers.