The morphological characters of the pigeon endocrine pancreas during the post-hatching life were investigated through three different ages to judge the possibility of diabetes development with age. The study depended on histological and immuohistochemical techniques. The present investigation revealed that the endocrine pancreas of the pigeon differentiates into two types of langerhans islets; dark islets and mixed islets. These two types of Lagerhans islets were observed in different ages of the pigeon. However, the cellular composition of the islets is differed. Dark islets comprise glucagon and somatostatin immunoreactive cells. Mixed islets consist of insulin, glucagon, somatostatin immunoreactive cells plus pancreatic polypeptide immnuoreactive cells in only adult and aged pancreas. The percentage of glucagon (A) immunoreactive cells increase with age. The percentage of insulin (B) immunoreactive cells is higher in the young pigeons, declines in the adult and becomes lower in the old pigeons. The high percent of glucagon (A) cells confirmed that glucagon in indispensable for the maintenance of life in birds. The decline of the insulin (B) cells percentage in the old pigeons represents a biological feature of age dependent risk of developing diabetes.
Histology, Immunology, Endocrine pancreas, Pigeon