Growth and proliferation stimulating effect of extremely small doses of nitrosomethylurea

The increase to 30-50% of spleen weight of intact and with La leukemia C57Bl/6 mice after 5 days i.p. anticancer drug nitrosomethylurea (10(-3)-10(-8) g/kg) injection was observed. The reaction of intact spleen was more expressed than that of leukemic spleen. The growth-stimulating effect of nitrosomethylurea supersmall doses was accompanied with perturbation in 3H-thymidine cell incorporation, that assume a certain change in cell proliferation.