Immunohistochemical Study of the Endocrine Cells in the Pancreas of the Korean Aucha Perch, Serranidae (Coreoperca herzi)

Serranidae (Coreoperca herzi) 췌장 내분비세포에 대한 면역조직화학적 연구

The regional distribution and relative frequency of some endocrine cells in the pancreas of the Korean aucha perch, Coreoperca herzi Herzenstein belonging to the family Serranidae in order Perciformis, were observed using specific mammalian antisera against serotonin, insulin, glucagon, somatostatin and human pancreatic polypeptide (hPP) by peroxidase antiperoxidase (PAP) method. The pancreas was divided into four portions (principal and secondary islets, exocrine and pancreatic duct regions). In addition, the pancreatic islet regions were further subdivided into three regions (central, mantle and peripheral regions). Spherical to spindle or occasionally round to oval immunoreactive (IR) cells were demonstrated in the pancreatic islets and exoccrine portions, but no cells were detected in the pancreatic duct portions. In the principal islets, serotonin-IR cells were not detected but most of insulin-IR cells were located in the central regions and they were also demonstrated in the mantle and peripheral regions in moderate and rare frequencies, respectively. Glucagon- and hPP-IR cells were mainly situated in the mantle regions but the cells were also demonstrated in the peripheral regions in relatively lower frequency. Somatostatin-IR cells were evenly distributed in the central and mantle regions in a few frequency and cells were also demonstrated in the peripheral regions in rare frequency. Cell clusters were consisted of hPP-IR cells that were situated in the peripheral to mantle regions. In the secondary islet portions, serotonin-IR cells were randomly distributed throughout the whole pancreatic islet regions but lower frequency was detected in the peripheral regions compared to that in central and mantle regions where cells were detected in a few frequency, respectively. Insulin-IR cells were restricted to the central regions in numerous frequency and glucagon-IR cells were evenly distributed in the mantle and peripheral regions in moderate frequencies, respectively. Somatostatin-IR cells were observed in the central and mantle regions in moderate and a few frequencies, respectively. In addition, hPP-IR cells showed similar distributional patterns to those of glucagon-IR cells except cells were also located in the central regions in rare frequency. In the exocrine portions, only glucagon- and hPP-IR cells were demonstrated in rare and a few frequencies, respectively. In conclusion, the regional distribution and relative frequency of pancreatic endocrine cells of the Korean aucha perch showed general patterns, which were observed in other teleost. However, some species-dependent different distributional patterns and/or relative frequencies were also demonstrated especially to serotonin-IR cells. In pancreas of the Korean aucha perch, insulin-IR cells were the most predominant cell type followed by glucagon-, somatostatin-, hPP- and serotonin-IR cells.