GIP: natural gut hormone that boosts insulin after meals
A hormone released by the small intestine after eating that signals the pancreas to produce insulin; also a key target of the diabetes and weight-loss drug tirzepatide (Mounjaro/Zepbound). Used as a lab research tool.
A researcher, an agent, or an algorithm wrote down the sequence and picked a target to hit.
An AI model like OpenFold3 or AlphaFold built a 3D structure and scored how well it fits the binding site.
A second contributor repeated the computation on their own hardware and the scores matched.
A chemistry service or a researcher ordered the sequence, it was manufactured, and mass spectrometry confirmed the right molecule was produced.
A binding or activity measurement confirmed that it actually does what the computer predicted — or didn't.
What this is
GIP (human) is the 42-amino-acid form of gastric inhibitory polypeptide — a hormone released by the small intestine after a meal that tells the pancreas to release more insulin. It is one of two "incretin" hormones in humans, alongside GLP-1 (Seino 2010). The full-length human hormone is 42 residues (Pederson 2016) and is the parent molecule for shorter naturally occurring forms — including the 39-residue variant tracked as /card/pep-10691 and the amidated 30-residue truncation GIP(1-30)NH₂. GIP matters today because its receptor, GIPR, is one of the two targets hit by tirzepatide and by newer investigational dual-incretin drugs being developed for type 2 diabetes and obesity (Véniant 2024, Bailey 2024).
History
The hormone that became GIP grew out of decades of work on "enterogastrones" — gut factors thought to inhibit stomach acid secretion. Pederson (2016) gives a first-person account of that arc: animal studies aimed at identifying acid-inhibitory factors led to the isolation of a 42-amino-acid polypeptide, which inhibited acid secretion in animal models, but whose role in human gastric physiology turned out to be unclear. Marks (2020) reviews the period 1969–2000, during which GIP's defining role was reframed from acid inhibition to glucose-dependent stimulation of insulin release. The GIP receptor was first characterized as a class B (secretin-VIP) family GPCR widely distributed in peripheral organs and the brain (Usdin 1993), and its ligand binding and signaling were mapped in transfected systems (Wheeler 1995).
What it does
GIP is released from K-cells of the upper small intestine in response to nutrients and acts on pancreatic β-cells to amplify glucose-stimulated insulin secretion — the core "incretin effect" (Seino 2010, Bailey 2024). Its action is glucose-dependent: GIP raises insulin output only when blood glucose is elevated, so it does not, on its own, drive hypoglycemia. GIPR is not restricted to the pancreas; it is also expressed in adipose tissue, bone, and the central nervous system (Usdin 1993), and GIP signaling at those sites has been studied in lipid handling and bone turnover (Bailey 2024). Together GIP and GLP-1 — both signaling through related class B GPCRs that raise intracellular cAMP in β-cells — account for the incretin component of post-meal insulin release (Seino 2010).
Mechanism
GIPR is a class B G-protein-coupled receptor that couples primarily to Gαs, raising intracellular cAMP in β-cells and other GIPR-expressing tissues; this potentiates glucose-triggered insulin secretion (Seino 2010, Wheeler 1995). The pharmacology of GIP at its receptor is exquisitely sensitive to terminal truncation: Hansen and colleagues (2016) showed that N- and C-terminally shortened forms of the naturally occurring amidated truncation GIP(1-30)NH₂ are high-affinity competitive antagonists rather than agonists at the human GIP receptor — a few residues at the N-terminus determine whether the ligand activates or blocks the receptor. Species differences are also large: Sparre-Ulrich and colleagues (2016) demonstrated that (Pro3)GIP, long used as a "GIP receptor antagonist" in rodent work, is in fact a full agonist at the human GIP receptor while behaving as a partial agonist/competitive antagonist at rat and mouse receptors. This is a meaningful caveat when reading any rodent GIP-antagonism literature: a tool compound called an antagonist in mice may be an agonist in humans. The stored sequence here is the canonical 42-residue human form; the active circulating pool in vivo includes both full-length GIP and the naturally truncated GIP(1-30)NH₂ form, which is itself C-terminally amidated (Hansen 2016) — an amidation that is not represented in the raw 42-letter sequence.
Evidence
- Human: GIP has been studied in human physiology for decades as one of the two principal incretin hormones (Seino 2010, Pederson 2016, Marks 2020). The GIP receptor — not GIP-the-peptide — is the clinical target: it is engaged by approved dual-incretin drugs (tirzepatide) and by investigational GIPR-antagonist conjugates such as AMG 133 (maridebart cafraglutide), which has progressed through phase 1 with weight-loss signals (Véniant 2024).
- Animal: GIPR pharmacology has been characterized across rat, mouse, and human receptor systems, with species differences large enough to flip an agonist into an antagonist (Sparre-Ulrich 2016). GIPR distribution beyond the pancreas — including adipose, bone, and brain — was mapped in early studies (Usdin 1993).
- In vitro: Ligand binding, cAMP coupling, and the consequences of N- and C-terminal truncation have been mapped in transfected cell systems (Wheeler 1995, Hansen 2016, Sparre-Ulrich 2016).
Known effects
- Glucose-dependent insulin secretion — Established physiological role; foundation of the incretin concept (Seino 2010).
- Adipose and bone signaling — GIPR is expressed outside the pancreas; GIP signaling has documented roles in lipid handling and bone turnover (Usdin 1993, Bailey 2024).
- Drug-target validation for obesity and T2D — GIPR is one of the two receptors engaged by tirzepatide and the converse target (antagonism) of the bispecific molecule AMG 133 (Véniant 2024, Bailey 2024).
Regulatory status
GIP (human) as the native 42-residue peptide is not a marketed drug. Its receptor, GIPR, is the clinical target: tirzepatide engages GIPR as one of its two receptor targets (Véniant 2024, Bailey 2024), and AMG 133 (maridebart cafraglutide) is an investigational bispecific molecule that antagonizes GIPR while agonizing GLP-1R (Véniant 2024). Regulatory approval status applies to those engineered molecules, not to GIP itself.
Related peptides
- GIP (1-39) (/card/pep-10691) — the 39-residue natural variant of GIP; same biology, shorter form.
- Glucagon (/card/pep-04430) — a related class B GPCR ligand; useful contrast for incretin/anti-incretin signaling.
- GLP-1 receptor agonists including semaglutide (/card/pep-00016), liraglutide (/card/pep-10868), and exenatide (/card/pep-04439) — engage only the GLP-1 arm of the incretin system, in contrast to GIP, which engages GIPR. Tirzepatide engages both.
Research directions for this peptide, selected from the current sources — hypotheses you can explore and model. None of it is proven yet; tap any one to see the full thinking.
Could the very beginning of the GIP hormone decide whether the cell releases insulin or starts to resist the drug?
If true, scientists could redesign the start of GIP to favor the signals that lower blood sugar while avoiding those that make the drug stop working over time, helping patients stay on therapy longer.
Could tying two specific parts of GIP together with a chemical bridge make it work better and wear out the receptor less?
If true, this design trick could lead to more effective diabetes and obesity drugs that keep working longer and cause fewer side effects for patients.
Could the GIP receptor have a hidden shape that current computer models do not see?
If true, drug designers could build better GIP-based medicines by targeting the receptor's true moving shape, potentially improving how well they work for people with diabetes or obesity.
Could this gut hormone enter the brain and switch brain immune cells from attack mode to repair mode?
If true, GIP-based drugs might one day slow diseases like Parkinson's or Alzheimer's, giving patients and families more healthy years beyond just treating diabetes.
Could taking GIP and GLP-1 as two separate injections control weight and blood sugar better than one dual drug?
If true, doctors could adjust each hormone dose to fit an individual patient, potentially getting better results with fewer side effects for people with obesity or type 2 diabetes.
Could the back end of the GIP hormone grab onto the cell surface to make its insulin signal last longer?
If true, drug makers could design GIP drugs with a stronger or weaker tail grip to control how long the medicine works, possibly creating longer-acting diabetes treatments without bigger injections.
▸full evidence table2 metrics
| metric | value | tool |
|---|---|---|
| ipTM | 0.7386026382446289 | boltz-2 |
| ranking score | 0.6171028017997742 | boltz-2 |
▸structural qualityopenfold3
| metric | value | note |
|---|---|---|
| gpde | 1.353 | global PDE — lower = better |
| disorder | NaN | fraction disordered |
▸3-letter notation
▸recipeboltz-2 1.0
| parameter | value |
|---|---|
| model | boltz-2 1.0 |
| weights | — |
| hardware | nvidia_nim_api |
| mlx version | — |
| python | — |
| random seed | — |
| msa strategy | none |
| diffusion samples | 1 |
| runtime | — |
| predicted by | mlx@peptide |
| predicted at | 2026-04-24 |
▸citationbibtex
@peptide{pep10689,
sequence = {YAEGTFISDYSIAMDKIHQQDFVNWLLAQKGKKNDWKHNITQ},
target = {gipr},
author = {peptidemodel},
year = {2026},
status = {synthesized}
}