In vivo dynamic distribution of 131I-glucagon-like peptide-1 (7-36) amide in the rat studied by gamma camera

Nucl Med Biol. 1999 May;26(4):413-20. doi: 10.1016/s0969-8051(98)00121-8.


The in vivo distribution of glucagon-like peptide-1 (7-36) amide (GLP-1) was studied in a rat model using radiolabeled GLP-1 (131I-GLP-1) depicted by a gamma-camera. The dynamic scan showed a rapid clearance from the blood circulation after an intravenous (i.v.) injection of 131I-GLP-1. After 10 min, the major part of the radioactivity was accumulated in the kidneys, whereas about 9% (of the blood value) was found in the brain. The pharmacokinetic study using 125I-GLP-1 demonstrated a rapid elimination from plasma, with a half-life of 3.3 +/- 0.6 min, a clearance of 117 +/- 15 mL/min, and a distribution volume of 557 +/- 61 mL. The elimination half-lives for the intact 125I-GLP-1 in lungs and kidneys were determined to 3.7 and 3.9 min, respectively. The metabolite GLP-1 (9-36) amide was followed in blood, lung, and kidney. All other organs assumed to contain low molecular weight fragments of GLP-1. The present study suggest that GLP-1 and/or its labeled metabolites cross the blood-brain barrier. Also the kidney plays an essential role in GLP-1 elimination after an i.v. administration, which can be of clinical interest especially in patients with kidney insufficiency who are treated with GLP-1.

MeSH terms

  • Animals
  • Brain / metabolism
  • Gamma Cameras
  • Glucagon
  • Glucagon-Like Peptide 1
  • Glucagon-Like Peptides
  • Iodine Radioisotopes*
  • Male
  • Metabolic Clearance Rate
  • Peptide Fragments / pharmacokinetics*
  • Rats
  • Rats, Sprague-Dawley
  • Tissue Distribution


  • Iodine Radioisotopes
  • Peptide Fragments
  • glucagon-like peptide 1 (7-36)amide
  • Glucagon-Like Peptides
  • Glucagon-Like Peptide 1
  • Glucagon