Partial agonism improves the anti-hyperglycaemic efficacy of an oxyntomodulin-derived GLP-1R/GCGR co-agonist

Mol Metab. 2021 Sep;51:101242. doi: 10.1016/j.molmet.2021.101242. Epub 2021 Apr 30.


Objective: Glucagon-like peptide-1 and glucagon receptor (GLP-1R/GCGR) co-agonism can maximise weight loss and improve glycaemic control in type 2 diabetes and obesity. In this study, we investigated the cellular and metabolic effects of modulating the balance between G protein and β-arrestin-2 recruitment at GLP-1R and GCGR using oxyntomodulin (OXM)-derived co-agonists. This strategy has been previously shown to improve the duration of action of GLP-1R mono-agonists by reducing target desensitisation and downregulation.

Methods: Dipeptidyl dipeptidase-4 (DPP-4)-resistant OXM analogues were generated and assessed for a variety of cellular readouts. Molecular dynamic simulations were used to gain insights into the molecular interactions involved. In vivo studies were performed in mice to identify the effects on glucose homeostasis and weight loss.

Results: Ligand-specific reductions in β-arrestin-2 recruitment were associated with slower GLP-1R internalisation and prolonged glucose-lowering action in vivo. The putative benefits of GCGR agonism were retained, with equivalent weight loss compared to the GLP-1R mono-agonist liraglutide despite a lesser degree of food intake suppression. The compounds tested showed only a minor degree of biased agonism between G protein and β-arrestin-2 recruitment at both receptors and were best classified as partial agonists for the two pathways measured.

Conclusions: Diminishing β-arrestin-2 recruitment may be an effective way to increase the therapeutic efficacy of GLP-1R/GCGR co-agonists. These benefits can be achieved by partial rather than biased agonism.

Keywords: Biased agonism; GLP-1; Glucagon; Oxyntomodulin; Partial agonism; β-arrestin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood Glucose / analysis
  • Blood Glucose / drug effects
  • Cells, Cultured
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / diagnosis
  • Diabetes Mellitus, Type 2 / drug therapy*
  • Disease Models, Animal
  • Glucagon-Like Peptide-1 Receptor / agonists*
  • HEK293 Cells
  • Hepatocytes
  • Humans
  • Hypoglycemic Agents / pharmacology*
  • Hypoglycemic Agents / therapeutic use
  • Islets of Langerhans
  • Liraglutide / pharmacology
  • Liraglutide / therapeutic use
  • Male
  • Mice
  • Oxyntomodulin / genetics
  • Peptides / genetics
  • Peptides / pharmacology*
  • Peptides / therapeutic use
  • Primary Cell Culture
  • Rats
  • Receptors, Glucagon / agonists*
  • Weight Loss / drug effects
  • beta-Arrestin 2 / metabolism


  • Blood Glucose
  • Glucagon-Like Peptide-1 Receptor
  • Hypoglycemic Agents
  • Oxyntomodulin
  • Peptides
  • Receptors, Glucagon
  • beta-Arrestin 2
  • Liraglutide