Features of the alpha-cell population organization in pancreas of spontaneously hypertensive rats (SHR)
DOI:
https://doi.org/10.14739/2310-1237.2017.2.109249Keywords:
α cells, glucagon, hypertensionAbstract
Alpha cells of pancreatic islets constitute the second largest population of pancreatic endocrinocytes, and the glucagon synthesized in them plays an important role in the regulation of glucose homeostasis. At the same time, glucagon-suppressive therapy is defined as the strategically main source of success of therapy for patients with type 2 diabetes mellitus. In clinical practice, diabetes is often associated with hypertension in the metabolic syndrome, which causes interest in the pathophysiology of α-endocrinocytes.
The aim of the study was to investigate the distribution parameters of α-cells in the pancreatic islets of SHR and to characterize the morphological and functional state of glucagon-synthesizing endocrinocytes
Materials and methods. In the histological sections of the pancreas, glucagon was detected by the immunofluorescence method; the area of pancreatic islets, as well as the number of α-cells in them, the concentration of immunoreactive glucagon in these cells, the specific indices of the distribution of islets, α-cells and glucagon per unit area of the gland. The results were processed with a package of statistical programs, to assess the reliability of the differences in the groups, the Student’s t-test and the Wilcoxon W-test were used.
Results. In normoglycemic SHR, the number of islets containing glucagon-synthesizing α-cells was 10% more (p <0.05) than in normotensive Wistar rats. In the pancreatic tissue, single α-endocrine cells were found in rats of both lines, not forming separate islets. In giant islets of SHR there were 72% more α-endocrine cells than in Wistar rats, and in large islets this difference was twofold. Accordingly, α-cells of these islets contributed significantly to higher glucagon levels in the pancreas of hypertensive rats: in giant islets, the amount of the hormone was 80%, and in large islets – 3.6 times higher than in normotensive rats. In this paper we discuss the mechanisms that lead to an increase in the number of α-cells in the pancreas of hypertensive rats.
Conclusions. 1). Pancreatic islets of normoglycemic SHR are characterized by an increase in the α-endocrinocyte pool, which number is 1.9 times greater than in normotensive Wistar rats. 2). In SHR in the pancreas, an increase in the specific glucagon content is observed, one’s amount is 2 times higher than that of normotensive rats of the Wistar line.
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