| Abstract: | The clearance of 51Cr-labelled Pseudomonas endotoxin from the blood was studied in calves in a nontolerant and in an endotoxin-tolerant state. Calves were rendered tolerant to the toxic effects of the endotoxin by four daily intravenous injections of endotoxin at the dose rate of 5 µg/kg body weight. Clearance of a small amount of 51Cr-endotoxin from the blood of nontolerant calves was almost complete within three minutes of injection and was not significantly faster in tolerant calves. The lungs and liver were the major organs involved in clearance of endotoxin from the blood. The 51Cr label was slowly excreted by the kidneys. Neither platelets nor leukocytes were demonstrated to participate in endotoxin clearance in calves. 51CrCl3 was injected into control calves. Relative to the distribution and loss of labelled endotoxin, the 51CrCl3 was cleared slowly from the blood, was distributed uniformly throughout the body and was excreted rapidly. |
