Oxyntomodulin - past, present and future

Almost since its discovery, glucagon was suspected to be formed in the gastrointestinal tract, and the L-cells were shown to contain glucagon-like immunoreactivity. This was due to the presence of two peptides that both contained the full glucagon sequence:glicentin of 69 amino acids and oxyntomodulin of 37 amino acids. While glicentin is a part of the glucagon precursor, proglucagon, and probably is inactive, oxyntomodulin, a fragment of glicentin, interacts although weakly with the glucagon as well as the GLP-1 receptor. However, in agreement with these activities, oxyntomodulin inhibited appetite and food intake in humans and inspired development of long acting, potent glucagon-GLP-1 co-agonists. Several such co-agonists are currently in clinical development and show promise because they combine GLP-1 like activities with those of glucagon agonism: additive weight loss and a stimulation of hepatic lipid metabolism with unique effectiveness on hepatic steatosis. They may therefore be effective in the treatment of metabolic dysfunction-associated steatotic liver disease (MASLD).