Distribution of 32P-labelled endotoxin in the frog.

Distribution and elimination of 32P-labelled endotoxin were studied in normal frogs and in frogs pretreated with a high dose of unlabelled endotoxin 24 hr previously. Like in other animals, the spleen and the liver of the frogs were found the most active R.E.S. organs. The alimentary tract too exhibited considerable R.E.S. activity. Pretreatment with unlabelled endotoxin resulted in a decrease of 32P-endotoxin uptake by the liver, the spleen and the alimentary tract. Evidence was obtained that the well-known effects of endotoxin on the R.E.S. of the mammals can be demonstrated in the frog as well.