Abstract
Summary
Repeated injections of leukocytic endogenous mediator (LEM) were given every 8 hr to rats for 10 days. Peripheral blood neutrophils were elevated rapidly and after several injections were maintained at six- to eightfold normal levels. Mature bone marrow neutrophils were depressed after the first injection and immature marrow neutrophils increased after the tenth 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. It was suggested that LEM in the presence of serum acts on mature mono-cytes to promote the release of CSF.
The authors thank Mr. Robert McArthur for his excellent technical assistance.
Get full access to this article
View all access options for this article.