Multiple choice K-cells secrete GIP (gastric inhibitory polypeptide). Where are these cells located? S-cells of duodenum M-cells of small intestine Mucosa of duodenum Pancreas Reveal answer Fill a bubble to check yourself C Correct answer Explanation GIP is produced by the K-cells. They are found in the mucosa of the duodenum and the jejunum of the gastrointestinal tract