代谢
各种降血脂药物以不同的方式诱导微粒体药物代谢酶。主要降低甘油三酯的氯贝丁酯、氯贝酸、非诺贝酸和双氯贝酸增加了细胞色素p450的含量(比对照组增加77-185%),尤其是细胞色素p452依赖的月桂酸12-羟基化酶活性(增加了5.6到8.4倍)。胆红素葡萄糖苷酸化增加了2.1到2.8倍;环氧化物水解酶活性(苯并(a)芘-环氧化物)仅略有增加。相比之下,仅降低血浆胆固醇的F1379没有改变细胞色素p450的含量,对月桂酸的12-羟基化略有影响。它显著增强了环氧化物水解酶活性(增加了7.6倍),并增加了平面基团I底物(4-硝基苯酚、4-甲基伞形酮、1-萘酚)的葡萄糖苷酸化(增加了200%)。这些效果伴随着肝脏中γ-谷氨酰转移酶的强烈阳性染色,特点是在组织门脉周围和腺泡周围区域有大量深色焦点。用F1379治疗大鼠三周并没有改变这种酶诱导的典型特征。这种持续效应可能揭示了一些具有重要毒理学意义的肝细胞生物化学变化。与母体化合物相比,用F1379的两个代谢物治疗大鼠导致了对环氧化物水解酶和UDP-葡萄糖苷酸转移酶形式的诱导活性降低;相反,细胞色素p450的含量增加了。
Various hypolipidemic agents differentially induced microsomal drug-metabolizing enzymes. Clofibrate, clofibric acid, fenofibric acid and dulofibrate, which are mainly hypotriglyceridemic, increased the content in cytochromes p450 (77-185% over control), and especially cytochrome p452-dependent lauric acid 12-hydroxylation (5.6 to 8.4-fold increase). Bilirubin glucuronidation was 2.1 to 2.8-fold stimulated; epoxide hydrolase activity (benzo(a)pyrene-oxide) was only slightly increased by the drugs. By contrast, F1379, which lowers plasma cholesterol only, did not change cytochromes p450 content and slightly affected the 12-hydroxylation of lauric acid. It dramatically enhanced the epoxide hydrolase activity (7.6-fold), and increased (200%) the glucuronidation of planar group I substrates (4-nitrophenol, 4-methylumbelliferone, 1-naphthol). These effects were accompanied by a highly positive staining of gamma-glutamyltransferase in the liver characterized by a great number of intensively colored foci in the periportal and perilobular area of the tissue. Treatment of rats for three weeks with F1379 did not modify this typical profile in enzyme induction. Such continuous effect could reveal some biochemical changes of hepatocytes with important toxicological relevance. Compared to the parent compound, treatment of rats with two metabolites of F1379 led to a decrease in the induction potency on epoxide hydrolase and on the forms of UDP-glucuronosyltransferase; by contrast, the content in cytochromes p450 was increased.
来源:Hazardous Substances Data Bank (HSDB)