[The EPR spectra of the ribonucleotide reductase in the tumorous tissues and organs of tumor-bearing animals].

Ribonucleotide reductase activity (RRA) has been studied in various tumors and spleens of tumor-bearing animals using EPR technique and biochemical methods. The effect of a number of biologically active compounds on RRA has also been studied. RRA in tumor and spleen increases during tumor growth. Inhibitory effect of irradiation, hydroxyurea, nitrosomethylurea and activatory effect of 5-nitrofurans and nitroimidazole derivatives on RRA has been observed. Regulatory factors of RRA and DNA synthesis in vivo have been discussed.