1. A simple quantitative method (based on McCarty’s method) of measuring the RN-ase activity in urine and blood is presented.
2. The RN-ase activity was examined in the blood and urine of patients suffering from chronic granulocytic leukemia, myeloblastic leukemia, lymphatic leukemia, granulocytopenia, lymphogranulomatosis, and in cases of infectious disease with an increased leukocytosis.
3. The RN-ase activity in the urine is increased in chronic granulocytic leukemia, while the RN-ase activity in the blood serum remains unchanged. In other diseases, in spite of an increased or decreased leukocytosis, no essential changes in the RN-ase activity in the urine and blood serum have been observed, which indicates that there is no close relationship between the number of leukocytes in the peripheral blood and the RN-ase activity in the 24-hour sample of urine.