Effect of Endotoxin on Granulopoiesis and Colony-Stimulating Factor

Abstract

To study the regulation of granulopoiesis, we measured the effect of endotoxin on peripheral leukocyte counts and on colony-stimulating factor (CSF) in the serum of CF₁ mice. The peripheral granulocyte level fell from 612 ± 69 (mean ± S.E.M.) to 147 ± 20 per cubic millimeter within 45 minutes of intraperitoneal injection of 5 μg of Salmonella typhosa endotoxin. In control animals, the CSF in 0.1 ml of serum stimulated the growth of 0.56 ± 0.4 in vitro myeloid colonies per 10⁵ cells. Forty-five minutes after endotoxin the CSF activity had increased to 7.7 ± 6.1 colonies per 10⁵ cells; after two hours it was 29.6 ± 10 colonies per 10⁵ cells.