An Immunohistochemical Study of the Insulin-, Glucagon-, Orexin A- and Ghrelin- Immunoreactive Cells in the Endocrine Pancreas of Guinea Pig

The present study was conducted to clarify the regional distribution and relative frequency of endocrine cells secreting insulin, glucagon, orexin A (OXA) and ghrelin in the pancreatic islets of guinea pig, by specific immunohistochemical methods. In the pancreatic islets, most of insulin-IR cells were detected in the central region, partially in mantle region. Glucagon-IR cells were located in the periphery of the pancreatic islets. In addition, they had lower frequency in the central region. OXA and ghrelinIR cells were identifed in central and peripheral regions of the pancreatic islets. Clearly, OXA-IR cells exhibited a characteristic distribution pattern resemble to those for the glucagonIR cells. However, ghrelin immunoreactivity exhibited a characteristic distribution pattern different from that of insulin-immunoreactive cells. In conclusion, some species-dependent unique distributions characteristics of endocrine cells in the pancreatic islets were observed in the guinea pig.