The answer is beta cells. The pancreas is known as mutually an exocrine and endocrine body part. The endocrine percentage of the pancreas is found in the Langerhans islets. In the islets, there are numerous cell types. The alpha cells, which are known to produce glucagon. The beta cells, which are known to produce insulin. The delta cells, which are known to produce somatostatin. The gamma cells, which are known to produce pancreatic polypeptide.