Possible Involvement of Leukocytic Endogenous Mediator in Granulopoiesis

Publisher Website
Google Scholar
Abstract
Repeated injections of leukocytic endogenous mediator (LEM) were given every 8 h to rats for 10 days. Peripheral blood neutrophils were elevated rapidly and after several injections were maintained at 6- to 8-fold normal levels. Mature bone marrow neutrophils were depressed after the 1st injection and immature marrow neutrophils increased after the 10th injection. Serum from rats receiving multiple LEM injections had increased amounts of colony-stimulating factor (CSF). Increased bone marrow colony stimulation also resulted when LEM was added directly to agar culture plates of bone marrow cells. This occurred only in the presence of rat serum and the population of adherent bone marrow cells. LEM in the presence of serum apparently acts on mature monocytes to promote the release of CSF.