Studies on tumor necrosis factor (TNF): II. Metabolic fate and distribution of human recombinant TNF.

We have evaluated the fate of cold and 125I- human recombinant tumor necrosis factor (RTNF) using isolated organs such as rabbit and monkey livers and rabbit kidney and lungs. We have also evaluated the body distribution of the total radioactivity after iv administration of 125I-RTNF in the rabbits. Monkey and rabbit livers play little catabolic role for RTNF. Lungs do not catabolize TNF at all, while the kidney appears to be the main catabolic organ. Accordingly, the body distribution of 125I-RTNF shows that most of the radioactivity is concentrated in the kidneys.