Kim S G, Cho J Y, Chung Y S, Ahn E T, Lee K Y, Han Y B
College of Pharmacy, Duksung Women's University, Seoul, Korea.
Drug Metab Dispos. 1998 Jan;26(1):66-72.
The effects of acriflavine (ACF), a protein kinase C inhibitor, on the expression of hepatic microsomal epoxide hydrolase (mEH), glutathione S-transferases (GSTs), and cytochrome P450 (P450) were assessed in rat hepatic tissue. Northern blot analysis revealed that treatment of rats with thiazole, allyl disulfide (ADS), oltipraz, or clotrimazole at a single dose of 100 mg/kg resulted in 7-18-fold increases in mEH mRNA levels at 24 hr, whereas concomitant ACF treatment (20 mg/kg, im) caused 50-95% inhibition of the chemical-induced increases in hepatic mEH mRNA levels. rGSTA2, rGSTA3, and rGSTM1 mRNA levels were also significantly suppressed at 24 hr in response to a single dose of ACF (20 mg/kg, im). Animals treated with both ACF and ADS showed complete blockage of mEH and GST gene expression as early as 12 hr after treatment. ADS-inducible increases in mEH and rGSTA2 mRNA levels were suppressed at 24 hr after treatment with ACF, in a dose-related manner, with 50% inhibitory dose (ID50) values of 2.0-2.3 mg/kg, whereas glyceraldehyde-3-phosphate dehydrogenase mRNA levels were not altered. Immunoblot analysis revealed that ACF (15 mg/kg/day, im, for 3 days) inhibited induction of mEH or rGSTA2 protein by ADS (100 mg/kg/day, po, for 3 days). The levels of hepatic P450 2B1/2, P450 2C11, and P450 3A1/2 were decreased in rats treated with ACF (15 mg/kg/day, im, for 3 days), whereas P450 1A2 and P450 2E1 expression was not affected. Treatment of rats with ACF in combination with gadolinium chloride, which inhibits mEH and GST expression through calcium channel blocking, shifted the dose-inhibitory response curves for ACF to the left, with 7-15-fold decreases in the ID50 values, indicating that the active site for ACF for suppression of mEH and GST mRNA levels differs from that for gadolinium chloride. Proflavine and safranine O, which are structurally related to ACF, also caused suppression of ADS-induced increases in mRNA levels, in a dose-dependent manner, with ID50 values of 4-9 mg/kg. These results demonstrate that ACF and its related compounds effectively suppress the expression of a battery of hepatic xenobiotic-metabolizing enzymes, including mEH, GSTs, and certain P450 forms.
在大鼠肝脏组织中评估了蛋白激酶C抑制剂吖啶黄素（ACF）对肝微粒体环氧化物水解酶（mEH）、谷胱甘肽S-转移酶（GSTs）和细胞色素P450（P450）表达的影响。Northern印迹分析显示，以100 mg/kg的单剂量用噻唑、烯丙基二硫化物（ADS）、奥替普拉或克霉唑处理大鼠，24小时时mEH mRNA水平增加7 - 18倍，而同时给予ACF处理（20 mg/kg，腹腔注射）可使化学诱导的肝mEH mRNA水平增加受到50 - 95%的抑制。对单剂量ACF（20 mg/kg，腹腔注射）的反应，24小时时rGSTA2、rGSTA3和rGSTM1 mRNA水平也显著受到抑制。用ACF和ADS两者处理的动物在处理后最早12小时就显示出mEH和GST基因表达完全被阻断。ACF处理后24小时，ADS诱导的mEH和rGSTA2 mRNA水平增加以剂量相关方式受到抑制，50%抑制剂量（ID50）值为2.0 - 2.3 mg/kg，而甘油醛-3-磷酸脱氢酶mRNA水平未改变。免疫印迹分析显示，ACF（15 mg/kg/天，腹腔注射，共3天）抑制了ADS（100 mg/kg/天，口服，共3天）对mEH或rGSTA2蛋白的诱导。用ACF（15 mg/kg/天，腹腔注射，共3天）处理的大鼠肝脏中P450 2B1/2、P450 2C11和P450 3A1/2的水平降低，而P450 1A2和P450 2E1的表达未受影响。用ACF与通过钙通道阻滞抑制mEH和GST表达的氯化钆联合处理大鼠，使ACF的剂量抑制反应曲线向左移动，ID50值降低7 - 15倍，表明ACF抑制mEH和GST mRNA水平的活性位点与氯化钆的不同。与ACF结构相关的硫酸黄素和番红花红O也以剂量依赖方式抑制ADS诱导的mRNA水平增加，ID50值为4 - 9 mg/kg。这些结果表明，ACF及其相关化合物能有效抑制一系列肝脏外源性物质代谢酶的表达，包括mEH、GSTs和某些P450形式。
