Accession Number : ADA013252


Title :   Regulation of Hemopoietic Stem Cell Turnover and Population Size in Neonatal Mice.


Descriptive Note : Scientific rept.,


Corporate Author : ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD


Personal Author(s) : McCarthy,K. F. ; MacVittie,T. J. ; Kirchgessner,P. J.


Report Date : APR 1975


Pagination or Media Count : 26


Abstract : Following birth the hematopoietic stem cell population of the liver as measured by the in vivo spleen nodule assay (CFU) declines with a halving time of about 48 hours. The stem cell population of the spleen grows exponentially with a doubling time of about 17 hours. In vitro incubation with high specific activity 3H-TdR and sedimentationn velocity studies indicate that CFU in neonatal liver and spleen are in cell cycle and that the distribution of the two CFU populations among the various stages of the cell cycle is similar in these two organs. It was also estimated by serial passage of single spleen colonies derived from neonatal liver and spleen CFU that both stem cell populations have a high self-renewal capacity. Thus, the decline in the neonatal liver stem cell population is not due to a lack of factors necessary to trigger CFU into cell cycle nor is the decline a function of the self-renewal capacity of the stem cell population itself. It is concluded that the factor(s) which triggers neonatal CFU into cell cycle is different from the factor(s) which regulates the size of the neonatal liver CFU population.


Descriptors :   *HEMATOPOIETIC CELLS, EXPERIMENTAL DATA, IN VITRO ANALYSIS, MICE, LIVER, IN VIVO ANALYSIS, CELLS(BIOLOGY), SPLEEN, BIOASSAY, LABORATORY ANIMALS, THYMIDINES.


Subject Categories : ANIMAL HUSBANDRY AND VETERINARY MEDICINE
      ANATOMY AND PHYSIOLOGY


Distribution Statement : APPROVED FOR PUBLIC RELEASE