GCG and colitis: Studies on animals have shown that GLP-1 and its analogues reduce inflammation in the gut and the gastrointestinal tract with a consequent lowering of the expression of proinflammatory cytokines (e.g., TNF-α, interleukin (IL)-1α, IL-1β, and macrophage colony-stimulating factor) in chemically induced rodent models of colitis [55,56].