The Glucagon-Like Peptide-1 (GLP-1) is a proglucagon-derived peptide with regulatory effects on many tissues, including the pancreas, stomach, liver, brain and heart. The rapid inactivation of intestinally secreted GLP-1 by DPP-4 enzyme raises the question of its production in proximity of its targets. Here we show some epithelial cells producing GLP-1 in the stomach of rats and humans. These cells respond specifically to intragastric load of glucose by increasing GLP-1 levels in the portal vein, in vivo in the rat. GLP-1 is known as an incretin, it decreases blood glucose levels after a meal by increasing insulin secretion in response to glucose. The increased GLP-1 secretion in obese individuals who have undergone bariatric surgery is considered as a keystone in the glycemic improvement observed in those patients. Here we show that obese rats that underwent RYGB or VSG exhibit a new gastric mucosa phenotype with expansion and hyperplasia of the mucus neck cells, and increased density of gastric GLP-1 expressing cells compared to sham animals. These findings highlight a potential role of stomach-derived GLP-1 in the outcomes of bariatric surgeries and raise the question of its role in physiology and metabolism.