Gastric inhibitory peptide (GIP) (22-51), a pro-atherogenic peptide comprised of 30 amino acids from the residues 22-51 of its precursor protein proGIP, is present in human plasma. It activates the degradation of IκB-α and the nuclear translocation of NF-κB in both macrophage-differentiated THP-1 cells and human aortic endothelial cells at a concentration of 1 µM. Additionally, in ApoE-/- mice, GIP (22-51) escalates the area of atherosclerotic lesions and plaque development in vivo.