The C-terminal extension of exendin-4 provides additional metabolic stability when added to GLP-1, while there is minimal effect of truncating exendin-4 in anaesthetized pigs

► Exendin-4, unlike native GLP-1 is cleared solely via the kidneys. ► Renal clearance of GLP-1 exceeds the glomerular filtration rate. ► Exendin-4 differs from GLP-1 by having a COOH-terminal extension. ► We investigated the importance of this extension in anaesthetized pigs. ► Addition of the extension of exendin-4 to GLP-1 reduced its metabolic clearance.