抄録
The cytoplasmic proteins of rat liver following exposure to the hepato-carcinogen, 3'-methyl-4-dimethylaminoazobenzen (3'-MDAB) were separated by a two-dimensional gel system using isoelectric focusing in the first dimension and sodium dodecyl sulfate (SDS) gel electrophoresis in the second dimension. After commencement of administration of the carcinogen, the rats were sacrificed at 14 weeks (hepatoma A) just after the occurrence of hepatomas, 16 weeks (hepatoma B), and 22 weeks (hepatoma C), respectively. All three hepatomas have six protein spots that have not been found in normal liver; i.e., 35/7.8 and 20/7.3 (molecular weight × 10-3/isoelectric point) as repre-sentative proteins. Some proteins 72/6.8, 72/6.3, 65/7.3, and 44/7.8 which were present in hepatoma, were found in large amounts in accordance with the tumor growth. The patterns of spots of cytoplasmic proteins in liver showed alterations during the course of carcinogenesis, and finally those of hepatoma C were very different from those of normal liver. These changes in composition of cytoplasmic proteins reflect earlier changes in the rate of synthesis of individual protein species.
