Fate of injected interleukin 1 in rats: sequestration and degradation in the kidney

Cytokine. 1990 Nov;2(6):416-22. doi: 10.1016/1043-4666(90)90050-4.


The tissue distribution and route of clearance of human recombinant interleukin 1 alpha (IL 1 alpha) injected intravenously in rats was studied. The plasma half-life was approximately 2.5 min, and this was increased after nephrectomy, the kidney being the major organ through which the IL 1 alpha was excreted. Two iodinated fragments of IL 1 alpha, of approximately 5 and 9 kDa, were excreted by the kidneys whereas only intact, 17-kDa IL 1 alpha was detected in plasma, suggesting that the protein was being degraded after uptake by the kidney. The results of in vivo experiments in which surface endopeptidase-24.11 was inhibited with phosphoramidon and in vitro experiments in which rat kidney homogenates were incubated with radiolabeled IL 1 alpha suggest that the cytokine was endocytosed and then hydrolysed by lysosomal proteinases.

MeSH terms

  • Animals
  • Autoradiography
  • Half-Life
  • Humans
  • Interleukin-1 / metabolism*
  • Interleukin-1 / pharmacokinetics
  • Iodine Radioisotopes
  • Kidney / metabolism*
  • Male
  • Molecular Weight
  • Nephrectomy
  • Peptide Fragments / isolation & purification
  • Rats
  • Rats, Inbred Strains
  • Recombinant Proteins / metabolism
  • Recombinant Proteins / pharmacokinetics
  • Time Factors
  • Tissue Distribution


  • Interleukin-1
  • Iodine Radioisotopes
  • Peptide Fragments
  • Recombinant Proteins