Cr⁵¹-labeled endotoxin distribution in granulocytopenic animals

¹ Department of Medicine, University of North Carolina School of Medicine, Chapel Hill, North Carolina

Endotoxin, injected intravenously in small doses, is removed from the blood of nongranulocytopenic and granulocytopenic, HN₂-treated rabbits at a rate similar to normal controls, but more slowly than in tolerant animals. Significant nonplasma activity is present in animals with only a few circulating granulocytes, re-emphasizing the role of platelets in binding endotoxin. In addition to the liver and spleen, the bone marrow is a significant reservoir for endotoxin removed from the blood, even in animals with markedly hypocellular marrows. Thus, granulocytes would not appear to contribute significantly to the removal of small doses of endotoxin. Pretreatment of rabbits with HN₂ does not appreciably alter either the clearance of endotoxin from blood or its distribution in tissues.

Key Words: radiolabeled chromium • leukopenia • blood cells, thrombocytes • nitrogen mustards • reticuloendothelial system • endotoxin tolerance • rabbits • radiochromium-labeled endotoxin • blood clearance of endotoxin • tissue distribution of endotoxin

Submitted on October 2, 1963