Metabolic and neuroendocrine
GLP-1 receptor signalling
Activation of the glucagon-like peptide-1 receptor enhances glucose-dependent insulin secretion, suppresses glucagon when glucose is elevated, slows gastric emptying and influences central appetite pathways.
Biological pathway
GLP-1 receptor agonism → Gs protein activation → increased cyclic AMP → glucose-dependent pancreatic effects plus gastrointestinal and central satiety signalling.
Evidence summary
The mechanism is supported by pharmacology, clinical biomarker responses and large randomized trials of licensed GLP-1 receptor agonists.
Limitations
Clinical effects vary by molecule, dose, population and treatment duration. Weight regain after treatment withdrawal is common, and the contribution of each downstream pathway cannot be isolated in routine clinical studies.