GLP-1 (glucagon-like peptide-1) is an incretin hormone released from intestinal L-cells after nutrient intake. It is produced by tissue-specific processing of proglucagon — the same precursor that yields glucagon in pancreatic alpha-cells — and circulates mainly as the active forms GLP-1(7-36)amide and GLP-1(7-37).
Biology as reported
GLP-1 binds the GLP-1 receptor, a class B G protein-coupled receptor expressed on pancreatic beta-cells and in the brainstem, hypothalamus, heart and vagal afferents. Receptor engagement raises intracellular cAMP; the literature describes glucose-dependent insulin secretion, suppression of glucagon release, slowed gastric emptying and reduced food intake in animal and human studies. Native GLP-1 has a plasma half-life of roughly two minutes because DPP-4 cleaves the peptide after its second residue, and renal clearance removes the rest.
Why it matters
That two-minute half-life is the entire reason engineered analogs exist. Aib substitution at position 8 blocks DPP-4, and fatty-acid acylation promotes albumin binding, together stretching duration from minutes to days. Semaglutide and liraglutide are GLP-1 receptor agonists built this way.
Related terms
incretin · GIP · glucagon receptor · half-life. Browse GLP-1 and incretin peptides, the GLP-1 research family, or Semaglutide.