Analysis of glucagon-like peptide 1; what to measure?

Clin Chim Acta. 2011 Jun 11;412(13-14):1191-4. doi: 10.1016/j.cca.2011.03.010. Epub 2011 Mar 15.


Background: Glucagon-like peptide 1 (GLP-1) is a gut hormone which acts as an incretin and is therefore of major interest in treatment of type II diabetes mellitus. GLP-1 circulates in many different forms, some of which are biologically active and others are not. Our hypothesis was that various methods to measure GLP-1 detect different forms of GLP-1, which may cause confusion when comparing results.

Methods: We compared three assays, the GLP-1 (active) ELISA (Linco research; ELISA(LINCO)), GLP-1 (total) RIA (Linco research; RIA(LINCO)) and the total GLP-1 RIA developed by the group of Holst (RIA(HOLST)) on specimens obtained during meal studies. In addition, we studied the effect of addition of a DPP-4 inhibitor.

Results: The correlation between RIA(LINCO) and ELISA(LINCO) was highest (r=0.76; n=35; p<0.01), whereas results of RIA(HOLST) correlated less with those of RIA(LINCO) and ELISA(LINCO) (r=0.35 and 0.39 respectively; n=35; p<0.05). GLP-1 results measured with ELISA(LINCO) were higher (median 28%; p<0.001) upon addition of the DPP-4 inhibitor.

Conclusion: Two commercially available GLP-1 assays do not necessarily give results equal to the well-defined GLP-1 assay developed in Copenhagen. Absolute values are also different due to differences in standardisation. Moreover, assays detect different forms of GLP-1, which hampers comparison to published data.

MeSH terms

  • Clinical Chemistry Tests / methods*
  • Dipeptidyl Peptidase 4 / metabolism
  • Dipeptidyl-Peptidase IV Inhibitors / pharmacology
  • Enzyme-Linked Immunosorbent Assay
  • Glucagon-Like Peptide 1 / analysis*
  • Humans
  • Postprandial Period


  • Dipeptidyl-Peptidase IV Inhibitors
  • Glucagon-Like Peptide 1
  • Dipeptidyl Peptidase 4