The effect of hydrocortisone on human granulopoiesis in vitro with cytochemical analysis of colonies

In order to clarify the regulation of granulopoiesis by hydrocortisone in humans, we investigated the effect of glucocorticoids on the formation of granulocyte and/or macrophage colonies. By means of the dual esterase staining techniques applied to whole mount preparations of agar culture dishes, we examined the granulocyte-macrophage colony type. It was revealed that hydrocortisone stimulated the formation of neutrophil-containing colonies and inhibited macrophage colony formation. There was a significant increase in neutrophil colonies when the cells were preincubated with hydrocortisone for only 24 h. Delayed addition of hydrocortisone to the cultures was less effective in increasing the proportion of neutrophil colonies than addition at the beginning of culture. Moreover, addition of hydrocortisone to T-lymphocyte- and phagocyte-depleted bone marrow cells also increased the number of neutrophil colonies and decreased macrophage colonies in the presence of CSF. These results suggest that hydrocortisone may affect granulocyte-macrophage precursors (CFU(GM)) in an early period of their differentiation.