DISTRIBUTION OF ENDOCRINE-CELLS DISPLAYING IMMUNOREACTIVITY FOR ONE OR MORE PEPTIDES IN THE PANCREAS OF THE ADULT VERVET MONKEY (CERCOPITHECUS-AETHIOPS)

Background: Our previous studies on the Chacma baboon revealed that th e most striking difference between islets of the ventral and dorsal re gions of the pancreas was their content of A and pancreatic polypeptid e (PP) cells with A cells predominating in the tail and PP cells in th e uncinate and head. Cells displaying dual immunoreactivity for both g lucagon and PP were also observed. The objective of this study was to establish baseline parameters of the adult Vervet monkey (Cercopithecu s aethiops) pancreas so that it could be used as a primate model to in vestigate possible therapies for diabetes. Methods: Vervet monkey panc reas was divided into uncinate, head, and tail regions, and the tissue processed for immunolabelling for pancreatic peptides using avidin-bi otin-peroxidase as marker. Dotblotting and absorption controls for ant ibody specificity were included because of the shared amino acid seque nces in pancreatic polypeptide (PP), neuropeptide Y (NPY), and peptide YY (PYY). Endocrine cell distributions and the percentages of each ce ll type per region were calculated for each monkey. Results: A signifi cant difference in the percentages of PP cells (P = 0.02) was observed between uncinate and tail regions, the distribution of NPY cells was similar to that of the PP cells, and all other distributions were simi lar to those reported in the literature for most animals studied. Cell s displaying dual immunoreactivity for glucagon and PP or NPY, PYY and NPY, or PP, PP and somatostatin and glucagon and insulin were identif ied and mapped throughout the pancreas. Most co-localizations occurred in the uncinate region. Co-localization of glucagon and insulin has n ot, to our knowledge, been reported previously in the adult pancreas. Conclusions: Pancreatic endocrine cell distribution in the adult Verve t monkey was found to be very similar to most other animals studied. T he occurrence of cells displaying dual immunoreactivity for a number o f different combinations of pancreatic peptides suggests an interestin g plasticity of endocrine cells even in the adult animal. (C) 1997 Wil ey-Liss, Inc.