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
Islets of Granada for the residents and for tourists. Hotels and shops are established on some of the islets, and boating tours are available. The fort of San Pablo is located on the islets in Lake Nicaragua. The fort of San Pablo was built in order to protect the city of Granada from Pirates in the 18th century. The San Pablo Fort on the Islets has witnessed the battles and conflicts endured during the Colonial Period. Many residents of the islands were forced to relocate to the mainland in the 1990s after having lived there for several generations. During Somoza's dictatorship, members of