Gut secreted incretin hormones and gastric bypass surgery currently provides some of the most successful treatments for diabetes and obesity respectively. However, despite the evident importance of the gut endocrine system no information exists on the total number and distribution of different types of endocrine cells in the gut. Here we have used the established preclinical Zucker Diabetic Fatty (ZDF) rat model which displays elevated levels of GLP-1 to assess L-cell distribution and L-cell dynamics in the full rostro-caudal extension of the rat intestinal tract.