RESUMO
The in vitro sensitivity of marrow CFU(E) to erythropoietin was assessed in normal, regenerating, and plethoric marrow and correlated to the cell-cycle distribution of the cells. Although all marrow samples demonstrated a approximately 75% S-phase distribution, regenerating, but not plethoric marrow, exhibited a 5- to 10-fold greater requirement for erythropoietin in vitro. It is concluded that altered responsiveness to erythropoietin may occur independently of alterations in the CFU(E) cell cycle. Secondly, alterations in erythropoietin sensitivity occur under conditions of marrow regeneration but not polycythemic suppression.
Assuntos
Medula Óssea/fisiologia , Ciclo Celular/efeitos dos fármacos , Células Precursoras Eritroides/fisiologia , Eritropoese/efeitos dos fármacos , Eritropoetina/farmacologia , Regeneração/efeitos dos fármacos , Animais , Ciclo Celular/fisiologia , Ensaio de Unidades Formadoras de Colônias , Células Precursoras Eritroides/citologia , Eritropoese/fisiologia , Feminino , Camundongos , Policitemia/fisiopatologiaRESUMO
The cell-cycle properties of marrow CFUE were assessed in normal regenerating cell preparations. In addition, the erythropoietin sensitivity of CFUE was correlated to the cell-cycle distribution of these cells. The results suggest a coupling of erythropoietin sensitivity to the S-phase of the CFUE cell cycle in so far as CFUE in G2/M/G1 were 2 to 10 times less sensitive to the hormone. It is concluded that the CFUE cell cycle per se is not a focus for erythropoietic regulation.
