Glucagon is secreted by: (PGI Nov 2010)

Ans: A (a cell) [Ref. Ganong 24th/432-33,23rd/316,328-30/The alpha cells, about 25 per cent of the total, secrete glucagonQ'The beta cells, constituting about 60 per cent of all the cells of the islets, lie mainly in the middle of each islet and secrete insulin and amylin, a hormone that is often secreted in parallel with insulin, although its function is unclear.The della cells, about 10 per cent of the total, secrete somatostatin0In addition, at least one other type of cell, the PP cell. is present in small numbers in the islets and secretes a hormone of uncertain function called pancreatic polypeptide.