The endocrine pancreas in the Australian wedge-tailed eagle (Aquila audax)--an immunocytochemical study

The endocrine pancreas of the Australian wedge-tailed eagle, Aquila audax, was investigated by means of immunocytochemistry using the PAP method at the light microscopic level. Serial paraffin sections were stained with haematoxylin and eosin, aldehyde fuchsin, and Grimelius' silver impregnation method in each of the lobes-dorsal, ventral, third and splenic lobes to show the morphology of the islet, B cells, and A cells respectively. The islets were of the 'mixed type' with no segregation into 'light' and 'dark' islets as in other birds studies (Falkmer and Ostberg, 1977). Semithin serial plastic sections were stained individually with primary antibodies for insulin, glucagon, somatostatin and pancreatic polypeptide (PP) in each of the four lobes. Positive regional differences noted were an increased concentration of insulin, glucagon, somatostatin and pancreatic polypeptide cells in the splenic lobe. Pancreatic polypeptide cells were present in all the lobes. There was no reciprocal relationship between PP cells and glucagon cells in the splenic lobe. These results in the feral bird (Aquila audax) differed from those of previous studies in domestic fowl pancreas (Phasianidae) (Tomita et al., 1985; Falkmer, 1985).