Table 1.

Differences between GLP-1 receptor agonists and DPP-4 inhibitors

Properties/action	GLP-1 receptor agonists	DPP-4 inhibitors
Application	Subcutaneous	Oral
“GLP-1” levels	Pharmacological (>5x)	Physiological (2–3x)
GLP-1 effects	Interaction with receptors on target organs (hormonal signal pathway)	Interaction with receptors on afferent nerves (mixed neural/hormonal signal pathway)
Duration of “GLP-1” elevation	Long, continuously	On-off, postprandially
Other mediators	No	GIP, PACAP, others
Effect on gastric emptying	Yes	None/scanty
Appetite	Reduced	Barely influenced
Effect on body weight	Weight loss	Weight-neutral
Adverse events	Nausea/fullness Exenatide: antibodies (?)	(Elevation of liver enzymes with vildagliptin in high doses?)

GIP gastric inhibitory polypeptide, PACAP pituitary adenylate cyclase activating polypeptide