A cytomorphological study of the endocrine pancreas of some Indian birds

Abstract

The anatomy and histology of the endocrine pancreas for 13 species of Indian birds representing diverse food habits and phylogenetic relations were studied. A lobulated organization of the pancreas, consisting of dorsal, ventral, and splenic lobes, was observed in all of the species studied. The distribution pattern of the islets of Langerhans was fairly similar in all species studied. In all birds, a distinct splenic lobe with a high percentage of islet tissue was observed. In all the birds, the largest islets were found in the splenic lobe, intermediate ones in the ventral lobe, and smallest ones in the dorsal lobe of the pancreas. The avian islets contained three types of cells: the alpha, beta, and delta cells. Topographically, cytologically, and tinctorially these cells showed a similar pattern in all species. The islets were found to be of two types: the large alpha islets, consisting mostly of alpha and delta cells, and the beta islets, containing beta, delta and sometimes alpha cells. A special feature of all avian species was the occurrence of a larger proportion of alpha cells than of either one of the other two cellular types. Another interesting finding is the relative abundance of delta cells in birds. The significance of these observations is briefly discussed.