Pattern of distribution of lipocalin 2 in the pancreas of diabetic rat

Abstract

Lipocalin 2 (LCN2), discovered in 1989, is an innate, inducible glycoprotein and a cytokine implicated in the regulation of inflammation and iron homeostasis. Although, LCN2 was thought to be present only in neutrophils, it has now been reported to be secreted by many other cells including adipocytes, hepatocytes and more recently, osteoblasts. LCN2 induces insulin secretion and suppress appetite by activating melanocortin‐4 receptors in the hypothalamus. Even though LCN2 has been associated with glucose homeostasis, the pattern of distribution and function of LCN2 in the pancreas of an animal model of diabetes mellitus has not been elucidated. The aim of this study was to determine whether LCN2 is present in the pancreas of diabetic and non‐diabetic Wistar rats. Immunofluorescence method was used to identify the pattern of distribution of LCN2 in pancreatic islet cells of Wistar rats. Co‐localization staining was also performed to determine whether LCN2 is located with either, insulin, glucagon, somatostatin, or pancreatic polypeptide (PP) in the islets of Langerhans. Immunofluorescence study shows that a large number of cells in the central region of rat pancreatic islet contains LCN2, where it co‐localizes mainly with insulin. LCN2 does not co‐localize with any other islet peptide. The number of LCN2 and insulin‐containing cells in pancreatic islets decreased significantly (p < 0.05) after the onset of diabetes. In conclusion, LCN2, a resident of pancreatic beta cells, may play a role in the regulation of insulin and glucose metabolism.Support or Funding InformationThis work was supported by UAE University Research Grant # G00002701