Simultaneous determination of incretin hormones and their truncated forms from human plasma by immunoprecipitation and liquid chromatography–mass spectrometry

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Vol. 803; no. 1; pp. 91 - 99
• Main Authors: Wolf, Raik, Hoffmann, Torsten, Rosche, Fred, Demuth, Hans-Ulrich
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15-04-2004
• Subjects: Chromatography, High Pressure Liquid - methods; Gastric Inhibitory Polypeptide - blood; Glucagon; Glucagon-Like Peptide 1; Glucagon-Like Peptides; Humans; Immunoprecipitation; Incretin hormones; Mass Spectrometry - methods; Peptide Fragments - blood; Precipitin Tests; Sensitivity and Specificity; Immunoprecipitation; Incretin hormones
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/j.jchromb.2003.11.044

The incretins, glucose-dependent insulinotropic peptide (GIP
1–42) and glucagon-like peptide 1 (GLP-1
7–36), are involved in regulation of gastric emptying, glucose homeostasis, body fat regulation and the glucose-induced insulin secretion from the endocrine pancreas. After release in the circulation both peptides are rapidly degraded by the exopeptidase dipeptidyl peptidase IV (DP IV) to the inactive polypeptides GIP
3–42 and GLP-1
9–36. In vivo stabilization of the active incretins by orally available DP IV-inhibitors is now widely accepted as a new therapeutic approach in antidiabetic treatment. In order to demonstrate the pharmacodynamic effect of DP IV-inhibitors, it is necessary to measure the plasma levels of active and inactive forms of GIP and GLP-1. We previously described an immunoprecipitation method as sample preparation and concentration in combination with a LC–MS analysis for determination of active and inactive GIP. We could improve the efficiency and suitability of this method by reduction of the necessary sample volume to 1.0
ml and simultaneous measurement of GIP
1–42, GIP
3–42 and GLP-1
7–36, GLP-1
9–36, without loss of sensitivity. An LOQ of approximately 5 and 11
pmol/l was maintained for GIP and GLP-1, respectively.