Some aspects of the mechanism of action of 1-propyl-1-nitrosourea

Abstract

Activation of RNA synthesis with simultaneous suppression of DNA synthesis in experiments with Ehrlich ascites carcinoma and 22 solid hepatoma in mice was observed 20–40 min after administration of 1-propyl-1-nitrosourea (PNU) in a dose of 10 mg/kg. Under these experimental conditions DNA biosynthesis in tumor cells was inhibited earlier than in spleen and in liver cells of tumor-bearing mice and control mice. Inhibition of synthesis of DNA and ribosomal and transfer RNA in the ascites cells, as well as of DNA and total RNA of the liver and spleen of tumor-bearing mice and controls, was observed on increasing the dose PNU to 200 mg/kg. PNU concentration of 10 −4 M was shown to induce RNA synthesis activation in vitro with simultaneous suppression of DNA synthesis in Ehrlich ascites carcinoma and leukemia L1210 cells PNU inhibits synthesis of arginine-rich histone and activates synthesis of lysine-rich histone; synthesis of saline-soluble proteins remains unchanged (at a PNU concentration of 10 −4 M).