Morphology and growth patterns of colonies of liver cell lines derived from rats fed with 4-dimethylaminoazobenzene

Morphological comparison at colonial level was made on a series of established liver cell lines derived from rats fed 4-dimethylaminoazo-benzene (DAB) for various periods of days for the purpose of elucidating more accurately the differences in morphology and growth patterns among these cell lines. Colonies of each cell line produced by the single cell plating technique were compared with regard to colony size, density and piling-up of cells, atypism and pleomorphism of cells, and the migration of cells from colonies. Plating efficiency of each cell line was also compared. The cultured rat liver cells obtained from those rats fed DAB for a longer period of days showed higher plating efficiency, and increased the incidence of large-sized, dense, and piled-up colonies, of colonies consisted of cells having nuclear atypism and pleomorphism, and of irregularly margined colonies with migrating cells. The correlation between the present results and the process of DABcarcinogenesis is discussed.