Comparative observations on AChE distribution in pancreas of some amphibians,reptiles and birds,with special reference to the islets of langerhans

Summary AChE activity in pancreas of some amphibians, reptiles and birds was investigated with light microscope using Karnovsky's technique.A nervous and an extranervous localization of the enzyme showing considerable qualitative and quantitative differences depending on the systematic group, could be discerned. Pancreatic peripheral cholinergic autonomic system comprises nerve fibers and perikarya. The latter seem to occur in newt and frogs as Cajal's interstitial cells (CIC) and are undoubtedly present in birds as CIC and as ganglionic cells. In lizard and snakes they were not present.The extranervous localization of AChE activity was observed in islet cells in frogs, lizards and snakes, also in the walls of blood vessels of all investigated poikilotherms.The findings are compared with results previously obtained in mammalian pancreas or in other organs. Some hypotheses on the physiological significance of enzyme presence in endocrine cells, as well as their belonging to APUD cell series are discussed.This work was supported by a fellowship of the Alexander von Humboldt-Stiftung, Bonn-Bad Godesberg and by the Deutsche Forschungsgemeinschaft (La 229-3). The author expresses his thanks to Prof. Dr. R. H. Lange for scientific advice.