Pancreatic islets by scarce alpha, delta and PP cells in the periphery, human islets display alpha and beta cells in close relationship with each other throughout the cluster. Islets can influence each other through paracrine and autocrine communication, and beta cells are coupled electrically to six to seven other beta cells (but not to other cell types). The paracrine feedback system of the pancreatic islets has the following structure: A large number of G protein-coupled receptors (GPCRs) regulate the secretion of insulin, glucagon and somatostatin from pancreatic islets, and some of these GPCRs are the targets of drugs used to treat type-2
Intestinal gland Intestinal gland In histology, an intestinal gland (also crypt of Lieberkühn and intestinal crypt) is a gland found in the intestinal epithelium lining of the small intestine and large intestine (colon). The glands and intestinal villi are covered by epithelium, which contains multiple types of cells: enterocytes (absorbing water and electrolytes), goblet cells (secreting mucus), enteroendocrine cells (secreting hormones), cup cells, tuft cells, and at the base of the gland, Paneth cells (secreting anti-microbial peptides) and stem cells. These cells are not all present in the colon. Intestinal glands are found in the epithelia of the small intestine, namely the