Cultivation of WISH cells in medium containing actinomycin D.

A dose of 0.0015 mug of Actinomycin D per 1 ml, applied for 4-5 days has some inhibitory effect on RNA and protein synthesis, leading to a diminished proliferation of WISH cells. This dose does not exert a destructive effect on cell morphology. Two to four times higher doses, applied for the same time were toxic. Morphological changes observed at various times of exposure of cells to different concentrations of drug as well as changes in cell proliferation are described. The attempts to select Actinomycin D-resistant cells have failed.