Oladapo O O, Forkert P G
Department of Anatomy, Queen's University, Kingston, Ontario, Canada.
Afr J Med Med Sci. 1995 Dec;24(4):395-402.
Multiple forms of cytochrome P450 exist some of which are selectively inducible by exposure of the organism to a variety of foreign compounds. In this study, a monoclonal antibody specific for 3-methyl-cholanthrene-inducible cytochrome P450, Mab 1-7-1, was used to detect, localize and quantify CYP1A1/CYP1A2 in livers of C57BL/6 mice. Mab 1-7-1 recognized a faint band in the range between 45-66 Kd in Western immunoblots of liver microsomes from control mice, and a strong band in the same range, in liver microsomes from beta-naphthoflavone-treated mice. Microsome from control liver contained minimal levels of CYP1A1/CYP1A2; pretreatment with beta-naphthoflavone caused an increase in their expression. Immunoelectron microscopy was used to demonstrate the cellular localization and quantification of these isozymes in the liver. The immunolabeling procedure confirmed the endoplasmic reticulum as the primary site of CYP1A1/CYP1A2 induction in hepatocytes. This organelle showed the highest labeling density after treatment with beta-naphthoflavone. Increase in CYP1A1/CYP1A2 was 33.4-fold by morphometric analysis in induced hepatocytes in comparison to non-induced cells. In conclusion, CYP1A1/CYP1A2 is highly induced by beta-naphthoflavone in C57BL/6 mouse liver, and the cellular site of expression is the endoplasmic reticulum.
细胞色素P450存在多种形式，其中一些可通过生物体接触各种外来化合物而被选择性诱导。在本研究中，一种针对3-甲基胆蒽诱导的细胞色素P450的单克隆抗体Mab 1-7-1，被用于检测、定位和定量C57BL/6小鼠肝脏中的CYP1A1/CYP1A2。Mab 1-7-1在对照小鼠肝脏微粒体的Western免疫印迹中识别出一条45-66 Kd范围内的 faint 条带，而在β-萘黄酮处理小鼠的肝脏微粒体中，在相同范围内识别出一条强条带。对照肝脏的微粒体中CYP1A1/CYP1A2水平极低；用β-萘黄酮预处理导致其表达增加。免疫电子显微镜用于证明这些同工酶在肝脏中的细胞定位和定量。免疫标记程序证实内质网是肝细胞中CYP1A1/CYP1A2诱导的主要部位。在用β-萘黄酮处理后，该细胞器显示出最高的标记密度。与未诱导细胞相比，通过形态计量分析，诱导肝细胞中CYP1A1/CYP1A2的增加为33.4倍。总之，CYP1A1/CYP1A2在C57BL/6小鼠肝脏中被β-萘黄酮高度诱导，其表达的细胞部位是内质网。
