氮烯乙茶在成年大鼠肝细胞中的生物转化

目的:建立成年大鼠肝细胞分离培养方法,探讨抗癌新药氮烯乙茶在肝细胞内生物转化。方法:用肝细胞活率、乳酸脱氢酶、能荷值变化观察肝细胞悬浮培养方法的稳定性,以高效液相色谱法测定肝细胞悬液中氮烯乙茶及其代谢产物的浓度。结果:氮烯乙茶在大鼠肝细胞内生成代谢产物7-乙基-8-氨基茶碱(7-ethyl-8-aminotheophylline,EAT) ,其最大反应速度Vm 为12-80 nmol·min^-1/106 cells,米氏常数Km 为640-9 μmol·L^-1 ,氮烯乙茶的固有清除率CLint为20-0 μL·min^-1/106 cells。结论:肝细胞培养的方法是考察药物生物转化的较好体外模型,同时氮烯乙茶具有降低肝细胞能荷值的作用。     

氮烯乙茶在离体大鼠肝脏灌流中的生物转化

用离体大鼠肝脏灌流方法,研究了抗癌新药氮烯乙茶(EDMTP)的生物转化过程。经HPLC和TLC分离纯化及光谱分析,鉴定了两个主要的代谢产物,EDMTP-Ⅰ为未经转化的原型药物,EDMTP-Ⅱ的结构为7-乙基-8-氨基茶碱。另外在静注EDMTP的小鼠血中也分离到EDMTP-Ⅱ,似可说明大鼠与小鼠对EDMTP生物转化的种属差异较小。     

雌二醇在人、比格犬和大鼠的肝微粒体中体外代谢比较研究

采用体外肝微粒体孵育体系, 研究雌二醇在大鼠、比格犬和人肝微粒体中酶代谢动力学及代谢产物差异。通过对雌二醇浓度、肝微粒体蛋白含量和孵育时间等条件的考察, 优化雌二醇与肝微粒体的反应体系; 应用LC-MS/MS定量检测孵育体系中的雌二醇及代谢产物, 分析比较雌二醇在3个种属、不同性别肝微粒体中代谢产物种类和生成量的差异, 计算并比较相应的动力学参数。在3个种属肝微粒体中均发现9个I相代谢产物, 且百分比有种属差异。结果表明, 3个种属的肝微粒体对雌二醇I相代谢途径基本相同, 但是代谢产物的生成量及雌二醇的药物代谢动力学性质存在一定的差异。     

噻吩诺啡在人、比格犬和大鼠肝微粒体中体外代谢比较

采用体外肝微粒体孵育体系, 研究噻吩诺啡在大鼠、比格犬和人肝微粒体中酶代谢动力学及代谢产物差异。通过对噻吩诺啡浓度、微粒体蛋白含量和孵育时间等条件的考察优化噻吩诺啡与肝微粒体的反应体系; 应用LC-MS/MS定量检测孵育体系中的噻吩诺啡及代谢产物, 分析比较噻吩诺啡在3种肝微粒体中代谢产物种类和生成量的差异, 计算并比较相应的动力学参数。噻吩诺啡在人肝微粒体中代谢转化最慢, 其相应的动力学参数K_m = (4.00 ± 0.59) µmol·L⁻¹、V_max = (0.21 ± 0.06) µmol·L⁻¹·min⁻¹、T_1/2 = (223 ± 6.10) min、CL_int = (117 ± 3.19) mL·min⁻¹·kg⁻¹; 比格犬和大鼠肝微粒体中相应的参数K_m、V_max、T_1/2和CL_int分别为 (3.57 ± 0.69) 和 (3.28 ± 0.50) µmol·L⁻¹、(0.18 ± 0.04) 和 (0.14 ± 0.04) µmol·L⁻¹·min⁻¹、(244 ± 1.21) 和 (70.7 ± 1.05) min、(213 ± 1.06) 和    (527 ± 7.79) mL·min⁻¹·kg⁻¹。在3个种属肝微粒体中均观察到噻吩诺啡的6个I相代谢产物, 但6个产物的相对生成百分比在不同种属肝微粒体中有一定差异。实验结果表明, 噻吩诺啡在体外人、比格犬和大鼠肝微粒体中主要的I相代谢途径相同, 但是代谢产物的生成量及噻吩诺啡的代谢动力学性质存在着一定的差异。     

罗通定在人、比格犬和大鼠肝微粒体代谢转化的体外比较研究

目的体外研究罗通定(rotundine,RTD)在大鼠、比格犬和人肝微粒体中酶代谢动力学及代谢产物差异。方法优化3个种属肝微粒体与RTD反应体系,应用LC-MS测定RTD在3种肝微粒体中的体外代谢消除,应用LC-MS/MS分析比较RTD在3种肝微粒体中代谢产物种类和生成量的差异,计算并比较相应的活性值。结果RTD在人肝微粒体中代谢转化最慢,其相应的动力学参数为Km=2.67μmol·L-1、Vmax=0.095μmol·L-1·min-1、T21=298±18.0min、CLint=14.6±0.91ml·min-1·kg-1;大鼠中相应的动力学参数为Km=3.24μmol·L-1、Vmax=0.122μmol·L-1·min-1、T12=71.0±2.30min、CLint=87.5±2.79ml·min-1·kg-1;比格犬中相应的动力学参数为Km=5.31μmol·L-1、Vmax=0.228μmol·L-1·min-1、T21=62.3±0.647min、CLint=139±1.43ml·min-1·kg-1。RTD在3个种属肝微粒体中均代谢产生4个O-去甲基后的羟基化同分异构体产物,但4个产物的相对生成百分比在不同种属肝微粒体中有一定差异。结论罗通定在体外人、大鼠和比格犬肝微粒体中主要的I相代谢途径相同,但是酶代谢动力学性质及代谢产物的生成量存在着一定的差异。     

顺式-和反式-阿霍烯在Caco-2细胞模型中的体外摄取、转运和外排特性

研究顺式-阿霍烯(Z-Ajo)和反式-阿霍烯(E-Ajo)的肠细胞摄取、转运和外排特性。采用体外培养的人结肠Caco-2细胞单层模型评价，应用高效液相色谱法测定Z-Ajo和E-Ajo的含量。结果表明，仅能在Caco-2细胞单层的顶侧检测到Z-Ajo或E-Ajo；阿霍烯在Caco-2细胞中的代谢可被抗氧化剂维生素C、细胞色素P450药物代谢酶3A亚型抑制剂甲吡酮和ATP抑制剂叠氮化钠所抑制。Z-Ajo和E-Ajo皆不能透过Caco-2单层细胞而被迅速代谢，其代谢与CYP450药物代谢酶有关。     

EFFECT OF SECRETAGOCUES ON PANCREATIC EXOCRINE SECRETION IN THE MONKEY AND THE DOG

The effects of secretin, cholecystokinin, dopamine, histamine and acetylcholine on the secretion of pancreatic juice were investigated in the monkey and the dog. In the resting state, bicarbonate concentration and the volume of pancreatic juice in the monkey were greater than those in the dog. However, the protein concentration of pancreatic juice in the monkey was less than that in the dog. Intravenous administration of secretin, cholecystokinin, histamine and acetylcholine caused a dose dependent increase in pancreatic secretion in both species. The responses in the monkey were greater than those in the dog. Dopamine caused pancreatic secretion only in the dog. The increase in bicarbonate concentrations of pancreatic juice induced by secretin and histamine in the monkey were greater than that in the dog. Increase in protein concentrations of the juice induced by cholecystokinin and acetylcholine in the monkey were less than that in the dog. However, pancreatic juice pH in both species was the same and was not affected by the secretagogues in the resting state or during the stimulation by secretogogues. From these results, it is concluded that there is a species difference in the secretory actions of the secretagogues in the monkey and the dog.     

狗肠系膜动静脉平滑肌的亚细胞膜酶活性和钙—累积功能之比较

从狗肠系膜动静脉平滑肌分离出不同部分亚细胞膜。其中微粒体部分(MIC)与浆膜F_2部分富含质膜成分,其膜标记酶活性分别为粗膜的4～5倍及10～12倍。酶活性在动静间存在组织差异。静脉MIC与F_2有较强Ca~(2+)结合和较弱的Ca~(2+)转运能力。     

年龄对大鼠肝脏生物转化功能及膜流动性的影响

通过与青年(3～4月)及中年(14月)组比较,研究了老年(24月)大鼠肝脏生物转化酶活性改变及膜流动性变化。结果表明,老年大鼠肝微粒体P-450含量、NADPH-细胞色素C还原酶活性无明显改变,但氨基比林N-脱甲基酶、苯胺羟化酶活性明显降低,且微粒体及胞浆GST、胞浆GSH-Px活性也明显下降;同时肝微粒体膜脂区流动性明显降低,膜Ch/PL值显著增大。研究提示,微粒体膜脂质环境及流动性变化与上述生物转化功能改变可能有一定的联系。     

D—氨基酸的生物转化与拆分技术研究的新进展

介绍了Ｄ－氨基酸的存在及其作用,着重综述了Ｄ－氨基酸的生物转化和拆分技术以及在生产制备中的应用。     

COMPARATIVE METABOLISM OF LOW CONCENTRATIONS OF BUTADIENE AND ITS MONOEPOXIDE IN HUMAN AND MONKEY HEPATIC MICROSOMES

The chronic (2-yr) inhalation toxicity of 1,3-butadiene (BD), a chemical used in large quantities to make rubber and plastics, differs greatly between mice and rats. Mice develop lung tumors after exposures to concentrations as low as 6.25 ppm, whereas rats develop mammary tumors only after exposures to 1000-8000 ppm BD. Extensive research has been carried out to determine where humans fit into this susceptibility range. Species differences in rates of metabolism of BD have been noted, but inconsistencies in metabolism data from different laboratories and some problems in the fit of physiologically based pharmacokinetic (PBPK) models with experimental data have left uncertainties. The experiments reported here are intended to clarify the issue of human metabolism of BD and to determine if metabolism of BD in cynomolgus monkeys is similar enough to metabolism in humans to use in vivo data from monkeys for PBPK modeling. The results indicate that for the reactions studied (oxidation of BD to the mono- and diepoxide), BD is metabolized substantially the same in monkey and human hepatic microsomes. The human metabolism data agreed with that reported earlier when the in vitro metabolism of BD was studied at low BD concentrations. Finally, BD at high concentrations was found to inhibit the further oxidation of its metabolite, the monoepoxide. Incorporation of this information on the competition between BD and its first oxidation product for CYP2E1 should improve the fit of PBPK models.     

右旋和左旋黄皮酰胺在大鼠体内代谢转化的研究

目的　研究黄皮酰胺在大鼠体内的代谢转化途径。方法　收集ip给药后大鼠的尿液、粪便及血液进行分析,寻找已知的代谢产物并通过HPLC-DAD和HPLC-MS分析寻找未知的代谢产物,确定大鼠体内的主要代谢途径。并通过比较(+),(-)-黄皮酰胺代谢的差异,初步研究其代谢转化的立体选择性。结果　HPLC分析发现,大鼠肝微粒体中所分离得到的6个主要代谢产物均在体内存在,(+),(-)-黄皮酰胺的代谢有明显的差异,根据MS碎片信息确定了一个新的代谢产物的结构,即N-去甲黄皮酰胺。结论　手性黄皮酰胺主要在肝脏中发生羟基化代谢反应,并有明显的立体选择性。     

EFFECTS OF ADRENALINE AND ISOPRENALINE ON HEPATIC VENOUS HAEMODYNAMICS AND VENOUS RETURN IN THE DOG

1. The effects of adrenoceptor agonists on venous haemodynamics were examined, utilizing the lower half perfusion method in dogs. 2. Femoral arterial pressure, central venous pressure, thoracic vena caval flow, abdominal vena caval flow, renal venous flow and femoral venous flow were measured simultaneously using electronic transducers and electromagnetic flow-meters. Hepatic volume change was monitored by the strain-gauge arch. 3. Single injections of both adrenaline (1.0 μ/kg) and isoprenaline (1.0 μg/kg) intra-aortically produced an increase in venous return, adrenaline transiently and isoprenaline continuously. 4. Epinephrine increased hepatic venous flow, while isoprenaline increased only abdominal vena caval flow. 5. These findings suggest that effects of α-adrenoceptors are more pronounced on the hepatic vein, while on other peripheral veins, effects of β-adrenoceptors are more pronounced.