Plasma glucagon-like peptide-1 (GLP-1)

Method

Plasma glucagon-like peptide-1 by immunoassay from serial postprandial sampling after a fixed mixed-nutrient drink or during intraduodenal nutrient infusion. Whether the assay captured the total or the intact/active fraction is recorded on the edge; the two fractions are not interchangeable and differ by the rate of DPP-4 degradation.

The method is part of the endpoint identity. Studies measuring the same quantity by a different method are held as separate endpoints.

Notes

Will be confused with glucose-dependent insulinotropic polypeptide, the other incretin measured on the same samples in the same reviews and reported in the same sentence. They come from different enteroendocrine cells (L-cell against K-cell), have different degradation kinetics, and PMID 37536867 grades the evidence for the two differently. Also distinct from plasma glucagon, which shares a name stem but is a pancreatic alpha-cell hormone whose beneficial direction is the OPPOSITE of this one.