Population changes of human somatic cells in culture during short-term treatment with drugs

The human somatic cell line VUPT was treated with 8-azaguanine or 5-bromo-2'-deoxyuridine for a week, then the drug was removed and cultivation continued in a standard medium. During or after the exposure to the drug various population parameters, such as morphological variability, frequency of multinuclear cells, total mitotic index, index of atypical mitoses, dispersion of chromosomal counts were evaluated. Increase in both morphological and karyological variability during the treatment with drugs was found but this increase was temporary and during one or two weeks of cultivation in a standard medium the initial phenotypic equilibrium of the population was restored. The meaning of such population changes is discussed.