THE MICROSCOPIC AND IMMUNOHISTOLOGIC ANATOMY OF THE ENDOCRINE PANCREAS OF PYGMY AND DWARF SPERM WHALES (KOGIIDAE)

Histologic studies of pancreatic tissues of one pygmy sperm whale, Kiogia breviceps , and one dwarf sperm whale, K. simus , demonstrated rather typical exocrine pancreatic anatomy. Peroxidase-antiperoxidase (PAP) techniques determined that the cell composition of the islets of Langerhans resembled that of other mammals. Within islets, cells secreting insulin (B-cells) and glucagon (A-cells), were clearly demonstrated, but, surprisingly, isolated A- and B-cells were also found among pancreatic acinar cells. PAP techniques demonstrated the presence of neuron-specific enolase within islets, but failed to provide a sufficiently clear reaction to demonstrate the presence of somarostatin-producing D-cells. No positive PAP reaction for serotonin occurred.