A hybrid peptide combining GLP-1 and CCK receptor activity reduced blood glucose, lowered body weight, and improved pancreatic beta-cell function in diabetic mice over 28 days of treatment.
Dual GLP-1 + CCK in one moleculeA single hybrid peptide activating both GLP-1 and CCK1 receptors reduced blood glucose and body weight in diabetic mice, aiming to synergistically combine two satiety pathways
What the researchers found
The hybrid peptide [Lys12Pal]Ex-4/CCK demonstrated prominent insulin-releasing (insulinotropic) actions in laboratory cell tests. When administered to diabetic high-fat-fed mice with chemically damaged pancreatic beta cells for 28 days, the dual-acting peptide produced significant reductions in blood glucose levels and body weight compared to controls.
Importantly, beta-cell function markers also improved, suggesting the peptide didn't just lower blood sugar temporarily but helped protect or restore the insulin-producing cells themselves. Both exendin-4 (a GLP-1 agonist) and CCK individually showed beneficial effects on beta cells, but the combined approach in a single molecule aimed to capture synergistic benefits of activating both pathways simultaneously.
Why it matters
Current GLP-1 drugs are already revolutionary for diabetes and obesity treatment, but they only target one pathway. CCK is another powerful satiety hormone that works through different mechanisms. Combining both signals in a single molecule could provide stronger appetite suppression, better blood sugar control, and more robust beta-cell protection than GLP-1 alone — potentially representing the next evolution beyond today's single- and dual-agonist drugs.
The numbers in context
28-day treatment; dual GLP-1/CCK1 receptor activation; significant reductions in blood glucose and body weight
How the study worked
The study first established the individual and combined effects of GLP-1 and CCK1 receptor activation on pancreatic beta cells in vitro. Researchers then characterized the bioactivity of an acylated (lipid-modified for longer action) dual-acting GLP-1/CCK hybrid peptide called [Lys12Pal]Ex-4/CCK. For the in vivo study, male C57BL mice were placed on a high-fat diet and given streptozotocin (STZ) to damage their beta cells, creating a model of obesity-related type 2 diabetes. Mice were treated with the hybrid peptide for 28 days, with measurements of blood glucose, body weight, insulin secretion, and beta-cell function markers.
Who was studied
Diabetic high-fat-fed mice with STZ-induced beta-cell damage
What this study cannot tell us
This was an animal study in mice with chemically induced diabetes, which doesn't perfectly replicate human type 2 diabetes. The abstract contains formatting artifacts that obscure some specific statistical values. The hybrid peptide has not been tested in humans. The 28-day treatment period is relatively short for assessing long-term efficacy and safety. High-fat-diet/STZ mouse models, while useful, may overestimate treatment effects compared to the slower progression of human disease.
How to read the evidence
This is an animal study using a mouse model of obesity-related diabetes. While it demonstrates the feasibility of dual GLP-1/CCK receptor targeting, the peptide has not been tested in humans and the disease model is artificially induced rather than naturally occurring.
When this study was published
Published in 2021, this study predates the explosion of interest in multi-receptor agonists driven by tirzepatide's success. The concept of combining GLP-1 with other gut hormone signals remains highly active in current drug development.
The bigger picture
The trend in metabolic drug development is moving from single targets (GLP-1 alone, like semaglutide) to dual agonists (GLP-1/GIP, like tirzepatide) to triple agonists (GLP-1/GIP/glucagon, like retatrutide). This study explores yet another combination — GLP-1 with CCK — expanding the repertoire of multi-receptor approaches. As researchers discover that different gut hormones provide complementary metabolic benefits, the number of possible combinations continues to grow, each potentially offering unique advantages for different patient populations.
Questions still open
- Would the GLP-1/CCK dual approach provide meaningful advantages over existing GLP-1/GIP dual agonists like tirzepatide in humans?
- Does the CCK receptor component add unique benefits for appetite suppression or beta-cell protection beyond what GLP-1 agonists achieve alone?
- Could a triple combination hitting GLP-1, CCK, and GIP receptors simultaneously offer even greater metabolic benefits?
Common questions
What is CCK and why combine it with GLP-1?
How is this different from existing drugs like tirzepatide?
Read the original research
Benefits of Sustained Upregulated Unimolecular GLP-1 and CCK Receptor Signalling in Obesity-Diabetes.
Frontiers in endocrinology, 12, 674704
Citation
Tanday, Neil; English, Andrew; Lafferty, Ryan A; Flatt, Peter R; Irwin, Nigel. (2021). Benefits of Sustained Upregulated Unimolecular GLP-1 and CCK Receptor Signalling in Obesity-Diabetes.. Frontiers in endocrinology, 12, 674704. https://doi.org/10.3389/fendo.2021.674704