ALTERATIONS OF NUCLEAR-PORES IN PRENEOPLASTIC AND NEOPLASTIC RAT-LIVER LESIONS INDUCED BY 2-ACETYLAMINOFLUORENE

The nuclear pore density and area were measured on freeze-fractured nu clei of ACI/N rat liver altered foci, adenomas and carcinomas induced by 2-acetylaminofluorene, and compared with those of normal hepatocyte s. The pore density of nuclei from these preneoplastic and neoplastic lesions was significantly higher than that of hepatocytes, but there w as no difference between lesions. The area of nuclear pores of the foc us cells did not differ from normal hepatocytes, whereas the areas of pores of adenoma and carcinoma cells were increased. Moreover, the nuc lear pore area of carcinomas was significantly greater than that of ad enomas. These results suggest that some changes may occur in nuclear p ores in the progress of tumorigenesis.