GCG and diabetes mellitus: Additionally, while high-fat fed mice with leptin resistance display increased GLP-1 content in the ileum and the colon, both fasting and glucose-stimulated GLP-1 secretion are significantly reduced in these mice (Anini and Brubaker, 2003), which may provide a link between leptin resistance in L cells and the reduced late phase (60–160 min) total and active GLP-1 secretion in patients with diabetes compared to healthy individuals (Vilsboll et al., 2001).