PREDICTION OF DRUG INTERACTION IN VITRO -FOCUSING ON CYTOCHROME P-450 3A AND P-GLYCOPROTEIN-

体外药物相互作用的预测 - 重点关注细胞色素 P-450 3A 和 P-糖蛋白 -

• 批准号: 10672153
• 负责人: SUGIMOTO Koichi
• 金额: $ 1.92万
• 依托单位: JICHI MEDICAL SCHOOL
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10672153/
• 关键词: Caco-2 cell; P-glycoprotein; cytochrome P-450 3A4; drug interaction; phenobarbital; rifampicin; digoxin; チトクロムP-450 3A4; Caco2; シクロスポリン; プロブコール

Using cultured Caco-2 cell monolayers, we tried to investigate the involvement of cytochrome P-450 (CYP) 3A4 and P-glycoprotein (P-gp) and to predict drug interaction of orally administered agents in vitro. Probucol, a lipid-lowering drug, caused P-gp-independent suppression of cyclosporine A (a substrate of CYP3A4 and P-gp) transport across Caco-2 cell monolayers. Pretreatment with various inducers failed to augment the P-gp-induced drug extrusion into the apical side of Caco-2 cell monolayers. Microsome fraction from Caco-2 cells even treated with CYP inducers did not demonstrate oxidization of nifedipine which is mediated by CYP3A4.We thus performed ex vivo experiments using intact rats. Microsome fractions from the intestinal epithelium and liver showed oxidation of nifedipine (averaged production rate ; 35 and 160 pmol/min/mg protein, respectively). We constructed ex vivo intestinal perfusion system and examined the absorption and secretion of P-gp substrate drug. P-gp inhibitor (verapamil, ketoconazole) increased the transport of digoxin, a P-gp substrate, to the adventitial side, and decreased the secretion into the luminal perfusate, indicating that this system can be used to assess the involvement of P-gp in the drug absorption at the intestinal tract. Treatment with phenobarbital, a CYP inducer, increased CYP3A4 activity in the liver (+ 130 %), but not intestinal epithelium. Another inducer, rifampicin, elevated CYP3A4 activity in the intestinal epithelium (+ 32 %) without affecting the activity in the liver. Rifampicin also enhanced the P-gp activity in the intestine. These results from ex vivo study suggest that CYP inducers may cause tissue-specific induction of CYP or P-gp activity. The mechanism of tissue-specific induction of drug metabolism or drug extrusion needs to be clarified. It may be helpful to understand the mechanism of drug interaction.

利用培养的Caco-2细胞单层，我们试图研究细胞色素P-450(CYP)3A4和P-糖蛋白(P-gp)的参与，并预测口服药物在体外的药物相互作用。普罗布考是一种降脂药物，可抑制环孢素A(CyP3A4和P-gp的底物)通过Caco-2细胞单层的转运，这是P-gp非依赖性的。不同诱导剂均不能增强P-gp诱导的药物向Caco-2细胞单层顶端的排泄。Caco-2细胞的微丝体组分即使用CYP诱导剂处理，也没有表现出由CYP3A4介导的硝苯地平的氧化。肠上皮和肝脏的微粒体部分显示硝苯地平的氧化作用(平均产生速率分别为35和160pmol/min/mg蛋白)。建立体外肠道灌流系统，考察P-gp底物药物的吸收和分泌情况。P-gp抑制剂(维拉帕米、酮康唑)增加了P-gp底物地高辛向外膜的转运，减少了向腔灌流液的分泌，表明该系统可用于评价P-gp参与肠道药物吸收的作用。用CYP诱导剂苯巴比妥处理后，肝脏中的CYP3A4活性增加(+130%)，但不能增加肠道上皮细胞的活性。另一种诱导剂利福平提高了肠上皮细胞色素P3A4的活性(+32%)，但不影响肝脏的活性。利福平还能增强肠道P-gp活性。这些来自体外研究的结果表明，CYP诱导剂可能引起组织特异性的CYP或P-gp活性的诱导。组织特异性诱导药物代谢或药物排出的机制尚需阐明。这可能有助于理解药物相互作用的机制。