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Title

Truncated (des-[27-31]) C-peptide is not a major secretory product of human islets

Authors
Paoletta, M.
Kahn, S. E.
Published in Diabetologia. 2002, vol. 45, no. 11, p. 1523-1527
Abstract AIMS/HYPOTHESIS: It has been suggested that C-peptide is bioactive and that such bioactivity is lost when the last five amino acids are removed. In rats, C-peptide is truncated in beta-cell granules leading to the loss of these last five residues and secretion of des-[27-31]-C-peptide. The aim of this study was to determine whether this truncated form of C-peptide was also a secretory product of human islets. METHODS: Plasma from healthy subjects, patients with Type II (non-insulin-dependent) diabetes mellitus or insulinoma and cord blood was analysed by HPLC and ELISA. This method allows for separation and quantification of intact C-peptide and des-[27-31]-C-peptide. Human islets were pulse-chased and secretion stimulated by a mixture of secretagogues. Radioactive products secreted to the medium were analysed by HPLC and the relative amount of intact and truncated C-peptide measured. RESULTS: The proportion of total C-peptide immunoreactivity comprised of des-[27-31]-C-peptide was 1.5% or less in all plasma samples, except for that from one patient with insulinoma where it was 4.2%. The proportion of radiolabelled des-[27-31]-C-peptide released from isolated islets was less than 1%. CONCLUSION/INTERPRETATION: In contrast to the situation in rats, des-[27-31]-C-peptide is not a major secretory product of human islets and its contribution to total circulating C-peptide is not increased in Type II diabetes or in patients with insulinoma.
Keywords AdultC-Peptide/ bloodChromatography, High Pressure LiquidDiabetes Mellitus, Type 2/bloodEnzyme-Linked Immunosorbent AssayFetal Blood/ chemistryHumansInfant, NewbornInsulinoma/ bloodIslets of Langerhans/ secretionPancreatic Neoplasms/ bloodPeptide Fragments/ bloodReference Values
Identifiers
PMID: 12436335
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PAOLETTA, M., KAHN, S. E., HALBAN, Philippe A. Truncated (des-[27-31]) C-peptide is not a major secretory product of human islets. In: Diabetologia, 2002, vol. 45, n° 11, p. 1523-1527. https://archive-ouverte.unige.ch/unige:8951

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Deposited on : 2010-07-12

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