This topic covers three receptors and the engineered peptides that engage them: the glucagon-like peptide-1 receptor (GLP-1R), the glucose-dependent insulinotropic polypeptide receptor (GIPR), and the glucagon receptor (GCGR). Their native ligands — GLP-1, GIP and glucagon — belong to the secretin-like peptide family. The design question that organizes the field is how many of them a single molecule engages, and with what selectivity.

It is among the fastest-moving areas in the current peptide literature and the easiest to overstate, which is why it is written conservatively. Guides here describe receptor pharmacology and the structure of an experiment. They do not describe outcomes.

What a guide in this topic covers

  • Which receptors a compound engages, and why the field's shorthand — single, dual, triple — is a starting point rather than a description. Single, dual and triple agonists differ in which receptors they engage and with what selectivity, and those differences matter more than the shorthand does.
  • The readouts. cAMP accumulation in receptor-expressing cell lines, competition binding against labeled reference ligands, and beta-arrestin recruitment and internalization assays. What is measured, and in what system.
  • Why the classes are studied together. Running a single, a dual and a triple agonist inside one assay framework lets the contribution of each receptor arm be isolated as an experimental variable.
  • What has to be controlled for any of that comparison to mean anything: reconstitution at a documented concentration, consistent storage, limited freeze-thaw handling, and material whose identity and purity are known, since truncated sequences or contaminants can shift apparent potency in cAMP and binding assays.

What this topic excludes

Everything downstream of the assay. No condition is named, no dose appears, and no compound is described as doing anything in a person or an animal. These are reference materials for in-vitro and laboratory work, supplied research use only.

Substantiation, including where it is missing

Identity data — CAS number, formula, molecular weight, PubChem CID — appears on a product page only where it can be verified against public databases and the mass recomputed from the formula. GLP3-RT is the exception in this topic: no public chemical-database record resolves for it, so its fields stay blank rather than carry an unsourced number, and it is the one compound here for which molarity cannot be stated, because that needs a verified molecular weight. Certificates of analysis are published lot by lot; where none is published, the product page says COA available on request.

What is in this topic today

One guide, Incretin & Metabolic Receptor Agonists: A Research Landscape, and the compounds listed below — of which MOTS-C is studied as a mitochondrial-derived peptide alongside the receptor agonists rather than as one of them. The catalog also carries cagrilintide, an amylin analog studied at the amylin and calcitonin receptors rather than the incretin ones, which has no guide here yet.