Different Degradation Rates of Alkylated RNA Protein and Lipids in Normal and Tumor Cells¹

In this paper it is shown that the radioactivity detected in DNA, RNA, proteins, and lipids 1 to 5 hr after N-methyl-N-nitrosourea-1-¹⁴C administration is retained in hepatoma cells for long periods of time (at least for 48 hr) while it is rapidly eliminated from liver and spleen cells. A hypothesis is suggested that emphasizes the role of turnover processes in mechanisms responsible for the selective toxicity of alkylating agents and nitrosoureas towards tumor cells.