Incretins & metabolic
The glucose-sensing peptides behind the modern metabolic toolkit.
GLP-1 · GIP · glucagon · amylin · insulin
Overview
Incretin hormones are released from the gut in response to a meal and amplify insulin secretion in a glucose-dependent way — the so-called incretin effect, where oral glucose triggers far more insulin than the same load given intravenously.
The two dominant incretins are GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide). Pharmacological agonism of their receptors — singly, or as GLP-1/GIP co-agonists — underpins the current generation of metabolic therapeutics studied for type 2 diabetes and weight regulation.
Surrounding the incretins sit the other metabolic peptides that set glucose tone: insulin and glucagon from the pancreatic islet, and amylin, co-secreted with insulin, which slows gastric emptying and modulates satiety.
Key signals
Incretin; glucose-dependent insulin release, slowed gastric emptying, central satiety.
Incretin; insulinotropic, with distinct adipose and CNS actions studied in co-agonism.
Counter-regulatory; raises hepatic glucose output, increases energy expenditure.
Co-secreted with insulin; slows gastric emptying, suppresses glucagon, promotes satiety.
Anabolic master switch for glucose uptake and storage.
Reference notes
- The incretin effect is blunted in type 2 diabetes, which motivated receptor-agonist pharmacology rather than incretin replacement.
- Receptor agonists are engineered for protease resistance and long half-life; native GLP-1 is degraded by DPP-4 within minutes.
- Dual and triple agonism (GLP-1/GIP, GLP-1/GIP/glucagon) is an active design frontier — the rationale is additive metabolic effects, not a single pathway.
- Muscle preservation during rapid weight loss is an open question driving interest in adjacent myostatin/activin pathways.
Analogs & therapeutics
Engineered molecules built on this family’s biology — same receptors, re-tuned for stability and duration.
A long-acting GLP-1 receptor agonist engineered for once-weekly dosing.
A dual GIP and GLP-1 receptor agonist — the first of the co-agonists.
A once-daily GLP-1 receptor agonist; an earlier acylated analog.
A GLP-1 receptor agonist derived from Gila monster venom (exendin-4).
An investigational GIP/GLP-1/glucagon triple receptor agonist.