In vivo biodistribution and pharmacokinetics of (18)F-labeled human C-peptide: evaluation in monkeys using positron emission tomography.

Abstract

The recently observed beneficial effects exerted by C-peptide in insulin-dependent diabetes patients (IDDM) have instigated research into the mechanisms of C-peptide action as well as the location for it. Here we report in vivo biodistribution studies performed in monkeys using positron emission tomography (PET) and C-peptide labeled in the N-terminal with fluorine-18. Following iv injection of the radiotracer, dynamic decay data were collected over the chest and/or abdomens of the monkeys. The radioactivity distributed mainly to the kidneys, less to the heart and to some extent to the liver. Excretion of radioactivity into the urinary bladder was observed. Brain uptake was not detected in a static emission scan of the head performed at late times. Accumulation of radioactivity in the skeleton as a result of in vivo defluorination was not observed. Pharmacokinetic modeling of the regional concentrations of radioactivity over time resulted, for most organs, in two-compartment models. The organs with the highest radioactivity concentrations have been identified, enabling dose estimations for studies in humans with low or no C-peptide.

• Authors: Anna Fredriksson, Karin Ekberg, Martin Ingvar, Bo-Lennart Johansson, John Wahren, Sharon Stone-Elander
• Journal: Life sciences (Life Sci) Vol. 71 Issue 12 Pg. 1361-70 (Aug 09 2002) ISSN: 0024-3205 [Print] Netherlands
• PMID: 12127157 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• C-Peptide
• Fluorine Radioisotopes
• Radiopharmaceuticals

Topics

• Amino Acid Sequence
• Animals
• C-Peptide (pharmacokinetics)
• Female
• Fluorine Radioisotopes
• Half-Life
• Humans
• Macaca fascicularis
• Male
• Molecular Sequence Data
• Radiopharmaceuticals
• Tissue Distribution
• Tomography, Emission-Computed