344-LB: A Highly Specific Chemiluminescent Assay That Accurately Measures Human and Rodent Glucagon

Glucagon is a hormone generated as a result of post translational modifications during proglucagon processing. The hormone's amino acid sequence is found in several proglucagon peptides, including the hormones glicentin and oxyntomodulin. In addition, glucagon’s sequence is similar to incretin hormones such as glucagon-like peptide-1 (GLP-1). The similar sequence homology between glucagon and these peptide hormones has created challenges in specifically measuring glucagon concentrations. Current commercially available glucagon assays have been proven to cross-react with oxyntomodulin, glicentin, and other proglucagon peptides. In addition, researchers often report higher cross-reactivity values than the manufacturers, which further complicates accurately measuring glucagon levels. To address this need, ALPCO has developed the STELLUX^® Chemi Glucagon ELISA for the quantitative determination of glucagon in EDTA plasma and cell culture samples. This assay has an excellent sensitivity and is capable of measuring post-prandial glucagon levels in both rodents and humans. Most importantly, this assay specifically measures glucagon without any cross-reactivity to other proglucagon peptides including glicentin and oxyntomodulin. In the current study, ALPCO’s ELISA was compared to competitor A’s ELISA to further investigate how differences in specificity contribute to final calculated concentrations of the analyte. A panel of 16 samples of human, mouse, and rat EDTA plasma were assayed on both products and an overall R² of 0.988 and slope of 1.337 was shown. The consistently higher recovery in values using the competitor ELISA may be explained through its known cross-reactivity with oxyntomodulin and/or glicentin. However, the correlation between the two assays would allow for a seamless transition from the competitor ELISA to the ALPCO ELISA within or between projects.