首页 | 本学科首页   官方微博 | 高级检索  
     


Induction of cytochrome P-450 in cultured rat hepatocytes. The heterogeneous localization of specific isoenzymes using immunocytochemistry.
Authors:R G Bars   A M Mitchell   C R Wolf     C R Elcombe
Affiliation:Biochemical Toxicology Section, I.C.I. Central Toxicology Laboratory, Macclesfield, Cheshire, U.K.
Abstract:Primary cultures of rat hepatocytes were exposed to phenobarbitone, clofibric acid, beta-naphthoflavone, isosafrole or dexamethasone for 3 days, and the induction of several cytochrome P-450 isoenzymes was demonstrated by increased catalytic activity, by Western blotting and by immunocytochemistry. The profiles of isoenzymes induced in vitro were compared with those induced in liver microsomes of rats dosed with the same agents. Clofibric acid, an agent which has not been thoroughly investigated previously, was shown to induce both in vivo and in vitro several P-450 isoenzymes normally inducible by phenobarbitone (PB1a, PB3a and PB3b) or steroids (PB2c). Immunocytochemical studies demonstrated that the inducible isoenzymes of cytochrome P-450 are not distributed evenly throughout the hepatocyte population, and increasing concentrations of phenobarbitone or beta-naphthoflavone in the medium results in an increasing proportion of 'induced' cells. However, whereas maximal concentrations of beta-naphthoflavone resulted in virtually all cells containing induced levels of MC1b, a maximal concentration of phenobarbitone resulted in only 30% of the cells containing induced levels of PB3a/PB3b. These results are discussed in relation to the heterogeneous distribution and induction of cytochrome P-450 in the intact liver.
Keywords:
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号