Table 1.

Summary of motor effects of GLP-1 and incretin-based therapies on the gastrointestinal tract.

	Gastric motility (delayed gastric emptying)	Small intestinal motility (delayed small intestinal transit)	Large intestinal motility (delayed colonic transit)
Endogenous GLP-1 (physiological dose)	One positive study [73]	No studies available	No studies available
Exogenous GLP-1 (pharmacological dose)	Strong evidence in human studies; healthy [16], obese [69], type 2 diabetic [12], critically ill [70]	Positive evidence in animal studies [74, 75]. Positive effect on fasting motility in humans [76]	Positive evidence in animal studies [77]. Only indirect evidence in humans [78, 79].
GLP-1 receptor agonists (e.g., exenatide, liraglutide)	Strong evidence with exenatide (healthy) [80], (type 2 diabetes) [80–82]. Some evidence with liraglutide [83, 84]	No studies available	No studies available
DPP-4 inhibitors (e.g., sitagliptin, vildagliptin)	Positive evidence with animal studies only [85]	No studies available	No studies available