Effects of dexamethasone on erythroid colony and burst formation from human fetal liver and adult marrow

Summary. Dexamethasone, a prototypic synthetic glucocorticoid, was added to cultures of human fetal liver and adult marrow cells to assess its effects on erythroid colony and burst formation. Dexamethasone decreased the number of fetal liver erythroid colonies and bursts formed in the presence of erythropoietin, and also decreased the number of cells per colony. The amount and type of haemoglobin produced per cell were unaffected by adding dexamethasone to the cultures. Dexamethasone inhibited the incorporation of ³H‐thymidine into DNA in fetal liver cells stimulated with erythropoietin, supporting the hypothesis that dexamethasone inhibits the proliferation but not the differentiation of fetal liver CFU‐E and BFU‐E. In contrast, addition of dexamethasone to adult bone marrow cultures had a variable effect on erythroid colony and burst formation.