[Distribution of colony-forming cells in the bone marrow and spleen of irradiated mice].

Two hours after the transplantation of 2-10(5) bone marrow cells 1.7--2.8% of the colony-forming units (CFU) persisted in the bone marrow and 14--16% -- in the spleen of the recipients. In 24 hours there was 1--2% of the CFU in the bone marrow and 21--26% in the spleen. The "F-factor" for these organs was constant in the recipients (under conditions of saturation) for 24 hours after the transplantation of 2.5.10(6)--1.7--10(7) bone marrow cells. The "F-factor" for the CFU seeding the spleen was 20--22% and for the CFU seeding in the femus--2,4--2,7%. It is supposed that the count of the CFU seeded in the total bone marrow volume was equal to that in the spleen. The average sum of the CFU seeding in the spleen and in the total bone marrow volume was about 40--50%. The fate of other CFU is unknown.