A Comparison of Avian Pancreatic Islets

The mammalian pancreas has a remarkable ability to maintain glucose homeostasis, through the production of the blood glucose lowering hormone insulin, and its counter‐regulatory hormone glucagon. The concept of avian diabetes arose in early studies by Minkowski in the late 1800's, which demonstrated that removal of the pancreas in domestic fowl and geese did not result in the development of diabetes. A species that deviates from this is horned owls which develop hyperglycemia and die following pancreas removal. Prior studies have demonstrated that the chicken pancreas contains more glucagon‐producing α cells compared to insulin‐producing β cells. This is reflected in low blood levels of insulin in chickens. We hypothesize that species differences may exist in the number of α and β cells in birds allowing some to persist after pancreatectomy, whereas other birds perish as a result of hyperglycemia. In the present study, we employed immunohistochemistry to localize α and β cells and Western blots to compare cell number in pancreatic tissue across avian species. Studies were conducted on Mourning dove, Hooded Siskin, Collared Warbling Finch, House Wren, Cinereous Conebill, Rufous Collared Sparrow, Amazilia Hummingbird, Carduelis Magellanica, and Mountain Parakeet.