Brasitus T A, Dudeja P K, Dahiya R, Brown M D
Biochim Biophys Acta. 1987 Jan 26;896(2):311-7. doi: 10.1016/0005-2736(87)90192-1.
Recently, work in this laboratory has shown that changes in the 'dynamic' component of fluidity, lipid composition and phospholipid methylation activity of distal colonic brush-border membranes could be detected after administration of 1,2-dimethylhydrazine to rats of the Sherman strain for 5-15 weeks, i.e., before the development of colon cancer. The present experiments were therefore conducted to: determine whether similar 'premalignant' biochemical changes could be detected in basolateral membranes of Sherman rats treated with this agent; and clarify the relationship of these membrane changes to the malignant transformation process by examining the effect of 1,2-dimethylhydrazine on these biochemical parameters in colonic antipodal plasma membranes of rats of the Lobund-Wistar strain. This particular strain of rats has previously been shown to be total resistant to the induction of tumors by 1,2-dimethylhydrazine. The results of the present experiments demonstrate that similar biochemical alterations could not be detected in the colonic plasma membranes prepared from either strain of rat treated with 1,2-dimethylhydrazine. These data support the contention that the prior biochemical membrane alterations noted in brush-border membranes of 1,2-dimethylhydrazine-treated animals are, in fact, related to the malignant transformation process and, furthermore, are confined to the luminal surface of distal colonic epithelial cells.
最近，本实验室的研究表明，给谢尔曼品系大鼠连续5至15周给予1,2 - 二甲基肼后，即结肠癌发生之前，可检测到远端结肠刷状缘膜流动性的“动态”成分、脂质组成和磷脂甲基化活性的变化。因此，进行了本实验，目的是：确定在用该试剂处理的谢尔曼大鼠的基底外侧膜中是否能检测到类似的“癌前”生化变化；通过研究1,2 - 二甲基肼对洛邦德 - 威斯塔大鼠品系结肠对侧质膜中这些生化参数的影响，阐明这些膜变化与恶性转化过程的关系。此前已证明该特定品系的大鼠对1,2 - 二甲基肼诱导的肿瘤完全具有抗性。本实验结果表明，在用1,2 - 二甲基肼处理的任一品系大鼠制备的结肠质膜中均未检测到类似的生化改变。这些数据支持这样的观点，即在1,2 - 二甲基肼处理动物的刷状缘膜中观察到的先前生化膜改变实际上与恶性转化过程有关，而且仅限于远端结肠上皮细胞的管腔表面。
