Abstract
Summary
Three peritoneal lavages at intervals of approximately 8-10 hr were performed in each of four splenectomized dogs. Induction of peritoneal inflammation and removal of neutrophilic cells from the peritoneal cavity was associated with a rapid mobilization of the neutrophilic band and segmented forms from the marrow into the blood and increased granulocytopoiesis in the marrow. The fluids removed from the peritoneal cavity contained both neutrophilic leukocytosis-inducing factor (LIF) and colony-stimulating factor (CSF) activities. The intensity of blood neutrophilia noted in dogs following the iv injection of fluids was considered to reflect LIF activity. CSF activity was assayed by the capacity of the lavage fluids to stimulate dogs'marrow cells to form granulocytic-macrophage colonies in vitro in soft agar medium. The increased LIF activity level was observed in lavages I, II, and III to approximately the same extent. This observation indicated that the production of LIF, having the function of mobilizing mature neutrophils from the marrow into the blood, continued as long as the peripheral demand for the cells existed. The CSF activity was maximum in lavage I and was precipitously reduced in lavages II and III. Following the increase of CSF level in lavages, the marrow M:E ratio, the percentage of myeloblasts + promyelocytes + myelocytes, and the granulocytic cellularity increased, which suggested that the CSF was influencing marrow granulocytopoiesis.
The pattern of fluctuation of the CSF activity in the lavages was different from that of the LIF activity, which indicated that CSF and LIF are two different entities.
We acknowledge the technical help of Ms. Louise Honikel and Mr. James Lehmann.
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