Duration of DNA synthesis in granulocytes during acute hyperplasia

Acute granulocytic hyperplasia was produced in mice by injection of endotoxin and, using the labelled mitosis method, the duration of DNA synthesis was compared to that in mormal mice. No difference was found. Taken in conjunction with previous studies using labelling indices, the results indicate that in mice showing acute granulocytic hyperplasia, there is only a moderate increase in proliferation of mitotable granulocytes. Thus the major factor responsible for hyperplasia is increased differentiation of precursor cells.