Summary: Researchers have developed a novel imaging method that reveals how dual agonist drugs such as tirzepatide interact with cells in the pancreas and brain to control blood sugar and appetite. Using fluorescent probes called daLUXendins, the team visualized how these drugs bind to insulin-producing beta cells and other pancreatic cell types, as well as to brain regions involved in feeding regulation.
The study found that GLP-1 and GIP receptors can cluster into tiny membrane nanodomains that may amplify signaling. These findings offer new insight into how dual agonists work and could speed the development of improved therapies for diabetes and obesity, including emerging triple agonists.
Key facts
- New imaging probes: daLUXendins permit real-time tracking of GLP-1 and GIP receptors in live tissue.
- Broader cellular targets: Probes bound most strongly to beta cells but also labeled alpha and delta cells within pancreatic islets.
- Brain access: Fluorescent tracers highlighted drug access to tanycytes and feeding centers, clarifying routes of appetite regulation.
Source: Oxford University
Overview
An international team from Leibniz-FMP, the University of Oxford, and the University of Birmingham has introduced a fluorescent imaging approach to trace how dual agonist molecules — modeled on tirzepatide — engage cellular targets in the pancreas and brain. Published in Nature Metabolism, the study presents daLUXendins, dual GLP-1R/GIPR agonist probes that enable direct visualization of drug–receptor interactions in living tissues.
The investigators synthesized fluorescently tagged analogues of dual-acting peptides that mimic tirzepatide’s ability to activate GLP-1R and GIPR. These daLUXendin probes come in non-lipidated and lipidated forms and were designed to provide clear, simultaneous detection of both receptor types without relying on often-unreliable antibodies.
Mapping metabolic drug targets in the pancreas
GLP-1R and GIPR are well known to regulate insulin release in the pancreas and to influence appetite through actions in the brain. Until now, precisely which pancreatic cell types respond to dual agonists in situ was difficult to determine. Using daLUXendins and super-resolution microscopy, the researchers demonstrated that these probes label pancreatic islet cells with an intensity ranking of beta cells greater than alpha and delta cells. This distribution helps explain multiple metabolic effects produced by dual agonists beyond their impact on insulin secretion alone.
Visualizing action in the brain
In the central nervous system, systemic administration of the fluorescent probes highlighted GLP-1R+ and GIPR+ neurons in circumventricular organs, regions where the blood–brain barrier is incomplete. The probes also labeled tanycytes—specialized glial-like cells that sense nutrients and relay metabolic signals to hypothalamic feeding centers. These observations shed light on how peripheral dual agonists can influence appetite-regulating circuits without widespread penetration into the protected brain parenchyma.
Receptor organization and implications for therapy
At the single-molecule level, daLUXendins revealed that GLP-1R and GIPR assemble into nanodomains whose composition and organization differ from those induced by single agonists. Such clustering may enable cumulative or amplified signaling when both receptors are engaged, offering a potential mechanistic basis for the superior glucose-lowering and weight-loss efficacy observed with dual agonists compared with GLP-1R-only drugs.
Although experiments were performed in mouse models using fluorescent surrogates of tirzepatide, the authors note the method can be adapted for human tissue and extended to study additional pharmacological targets, including next-generation triple agonists that include glucagon receptor activity. The work frames key questions for future research: how greater brain access might change efficacy or side-effect profiles, and how triple agonists alter receptor targeting and signaling compared with dual agonists.
Author comments and next steps
Professor David Hodson (Radcliffe Department of Medicine, University of Oxford) emphasized that simultaneous, live imaging of both receptors is a powerful way to identify which cells respond to treatment. Dr Johannes Broichhagen (Leibniz-FMP) highlighted the probes’ ability to reveal peptide dynamics and receptor organization at high resolution. The team plans to compare these dual agonist signatures with those produced by triple agonists to better understand differences in therapeutic potency.
About this research
Author: David Hodson
Source: Oxford University
Contact: David Hodson – Oxford University
Image credit: Neuroscience News
Original research: Open access. Title: “Fluorescent GLP1R/GIPR dual agonist probes reveal cell targets in the pancreas and brain” by David Hodson et al., Nature Metabolism. DOI: 10.1038/s42255-025-01342-6
Abstract (summary)
Dual agonists that target GLP-1R and GIPR are emerging as highly effective treatments for type 2 diabetes and obesity, showing greater glucose-lowering and weight-loss effects than GLP-1R agonists alone. To resolve the cellular targets of dual agonists, the authors developed daLUXendin and daLUXendin+, fluorescent dual agonist probes in non-lipidated and lipidated forms. These probes label rodent and human pancreatic islet cells with greater signal in beta cells than in alpha or delta cells, and they mark GLP-1R+ and GIPR+ neurons in circumventricular regions of the brain. Single-molecule imaging shows that dual agonists target endogenous GLP-1R–GIPR nanodomains with distinct organization compared with single agonists. The findings identify pancreatic and brain targets of dual agonists and argue that superior efficacy does not rely on broad brain penetration, offering new mechanistic insight to guide next-generation metabolic therapies.