GIP gut hormone: pig form used in insulin and obesity research
The pig version of a natural gut hormone that tells the pancreas to release more insulin after a meal; used only 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 (porcine) is the 42-amino-acid pig form of gastric inhibitory polypeptide — the gut hormone whose discovery established what we now call the "incretin" axis: a meal arrives in the small intestine, K-cells release GIP, and the pancreas puts out more insulin in response to the same blood glucose level (Yamada 2006). The porcine form is the original molecule that defined the hormone. It was isolated from pig small intestine before any human form was available, and most of the foundational GIP biology — from the original "enterogastrone" framing to the receptor-binding work of the 1980s — used the porcine peptide as the reference ligand (Marks 2020). The stored sequence (YAEGTFISDYSIAMDKIRQQDFVNWLLAQKGKKSDWKHNITQ) is the porcine 1-42 species variant; it differs from the human form at two positions — Arg18 and Ser34 in porcine, His18 and Asn34 in human (Moody, Thim and Valverde, FEBS Letters 1984) — so this card is the pig-origin reference peptide rather than the human hormone tracked as /card/pep-10689.
History
GIP began as a hunt for "enterogastrones" — gut factors thought to inhibit gastric acid secretion. The peptide that became GIP was isolated from porcine small intestine and named for that acid-inhibitory activity; over the following decade the defining biology shifted from acid inhibition to glucose-dependent stimulation of insulin release, and the name "gastric inhibitory polypeptide" was retained as a historical label even as the molecule's importance as an incretin overtook its original framing (Marks, Peptides 2020). The amino-acid sequence work on porcine GIP in the 1970s and early 1980s established the 42-residue structure, and the human form was isolated and sequenced from human small intestine in 1984, at which point the two-residue divergence at positions 18 and 34 was first reported (Moody, Thim and Valverde 1984). The receptor — GIPR, a class B (secretin–VIP family) G-protein-coupled receptor — was cloned from human tissue more than a decade later (Yamada, Genomics 1995), opening the door to the molecular and pharmacological GIPR work that underpins the modern dual-incretin drugs.
What it does
In pigs, infusion of porcine GIP raises plasma insulin in a glucose-dependent way and accelerates glucose clearance from the blood — the same incretin response later characterized in humans (Wolffbrandt 1986). Mechanistically, GIP binds GIPR on pancreatic β-cells; GIPR is a class B GPCR that couples primarily through Gαs to adenylate cyclase, raising intracellular cAMP and engaging PKA and Epac2 pathways to amplify glucose-stimulated insulin release. Beyond the β-cell, GIP signaling has been characterized in adipose tissue, bone, and the central nervous system, and animal work has shown GIPR contributes to pancreatic development and to physiological roles outside acute insulin secretion (Yamada 2006; Prasadan 2011). In contemporary obesity and type-2-diabetes research, GIP's signaling role is the basis for dual GIP/GLP-1 receptor agonist drugs such as tirzepatide (/card/pep-00017) — the dual agonism requires GIPR engagement: antagonising GIPR in human islets reduces the insulin response to tirzepatide (El et al., Nature Metabolism 2023; Coskun et al., Molecular Metabolism 2018). Porcine GIP is used in laboratory work as a well-characterized GIPR ligand against which agonist and antagonist pharmacology can be compared.
Evidence
- Human: Porcine GIP itself is a research reagent rather than a therapeutic, and is not the subject of registered human therapeutic trials. The downstream therapeutic relevance of GIPR pharmacology is in dual-incretin drugs (tirzepatide, retatrutide) developed on the human GIPR axis (Coskun 2018; El et al. 2023).
- Animal: Intravenous porcine GIP infusion in pigs produced glucose-dependent stimulation of insulin secretion and increased glucose clearance, establishing the incretin response in the species the peptide was originally isolated from (Wolffbrandt 1986). Mouse studies — including genetic ablation and embryonic-development work — have characterized GIP/GIPR roles in β-cell function, pancreatic development, and extrapancreatic physiology (Yamada 2006; Prasadan 2011).
- In vitro: GIP binding and Gαs / cAMP-mediated signaling at GIPR is characterized in transfected cell systems and in isolated human islets, including the work that maps the dual-incretin pharmacology of tirzepatide back to GIPR (Coskun 2018; El et al. 2023).
Known effects
- Glucose-dependent insulin secretion (incretin effect) — Established physiological role; characterized in pig and rodent in-vivo studies and in human islet preparations (Wolffbrandt 1986; Yamada 2006).
- β-cell signaling via Gαs / cAMP / PKA / Epac2 — Mechanistic, from GIPR receptor pharmacology (Yamada 2006).
- Extrapancreatic actions in adipose tissue, bone, and CNS — Reported in rodent genetic and pharmacological studies (Yamada 2006; Bailey 2024).
- Role in pancreatic development — Demonstrated in embryonic mouse pancreas (Prasadan 2011).
- Use as a reference GIPR agonist in pharmacological research — Including comparator pharmacology for dual GIP/GLP-1 agonists in clinical development (Coskun 2018).
Regulatory status
- US / EU: Not an approved drug. Porcine GIP is a research peptide; therapeutic agents acting at GIPR are separate molecules (tirzepatide /card/pep-00017 is the leading approved example).
- WADA: Porcine GIP itself is not separately listed; the WADA Prohibited List status that matters in this space attaches to specific commercial GIPR-targeted drugs rather than to the native incretin peptide as a research reagent.
Related peptides
- GIP (human) — the 42-residue human form; differs from this porcine sequence at residues 18 and 34.
- GIP (1-39) — a shorter naturally occurring insulinotropic GIP variant.
- Tirzepatide — the first approved dual GIP/GLP-1 receptor agonist; its therapeutic mechanism depends on GIPR engagement.
- Retatrutide — investigational triple GLP-1 / GIP / glucagon receptor agonist built on the GIP backbone.
- Semaglutide, liraglutide, exenatide — single-target GLP-1 receptor agonists, useful as a contrast class against GIP/GLP-1 dual incretin pharmacology.
- Glucagon — the counter-regulatory pancreatic peptide whose receptor is co-targeted in triple-agonist obesity drugs alongside GIPR.
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.
Does the arginine at position 18 of pig GIP create a stronger grip on the receptor than the near-neutral histidine found in human GIP?
If confirmed, researchers would know that old binding studies done with pig GIP cannot be directly compared to human GIP data, and drug designers could copy that stronger contact point to make better diabetes or obesity medicines.
Could a tiny fragment of just nine amino acids from the front of pig GIP activate the GIP receptor just as completely as the full hormone?
If true, it would be possible to build a very short and cheap peptide drug that fully activates the GIP pathway for treating diabetes or obesity, bypassing all the manufacturing complexity of synthesizing the full 42-residue hormone.
▸full evidence table2 metrics
| metric | value | tool |
|---|---|---|
| ipTM | 0.81276535987854 | boltz-2 |
| ranking score | 0.6754778623580933 | boltz-2 |
▸structural qualityopenfold3
| metric | value | note |
|---|---|---|
| gpde | 0.832 | 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{pep10692,
sequence = {YAEGTFISDYSIAMDKIRQQDFVNWLLAQKGKKSDWKHNITQ},
target = {gipr},
author = {peptidemodel},
year = {2026},
status = {synthesized}
}