INVIVO ERYTHROPOIETIN REQUIREMENTS OF REGENERATING ERYTHROID PROGENITORS (BFU-E, CFU-E) IN BONE-MARROW OF MICE

  • 1 January 1979
    • journal article
    • research article
    • Vol. 53  (6) , 1164-1171
Abstract
Erythroid progenitors (B-8, B-4, CFU-e [erythroid colony forming units]) in the femoral marrow of polycythemic mice were measured by in vitro culture assays after a single administration of BCNU [1,3-bis(2-chloroethyl)-1-nitrosourea] or Myleran. BCNU reduced pluripotent stem cells to 40% and erythroid progenitors to less than 5% of normal. B-8, the earliest erythroid progenitors, regenerated without erythropoietin (Epo) completely within 5 days. At 14 days after BCNU, intermediate progenitors (B-4) attained 60% of their normal numbers and CFU-e attained approximately 30%. Daily injections of Epo promptly restored normal B-4 numbers and near-normal CFU-e numbers in BCNU-treated mice. After Myleran, CFU-s [pluripotential stem cells] remained below 2% of normal for 14 days, and no regeneration of the B-8 occurred with or without daily Epo injections. Regeneration of B-8 was apparently dependent on cell inflow from the pluripotent stem cell compartment but was independent of the presence of Epo. Intermediate progenitors (B-4) required Epo and the presence of B-8 for complete and permanent regeneration. CFU-e were the most Epo-dependent of the 3 progenitors. B-4, recruited by Epo, required after their formation a 2nd exposure to the hormone to progress into the CFU-e stage.