Pancreatic somatostatin contents in spontaneously diabetic KK and non-obese diabetic (NOD) mice

Abstract

Alterations in the somatostatin (SRIF)-, insulin- and glucagon-containing cells were examined in two strains of spontaneously diabetic mice, KK and newly inbred non-obese diabetic (NOD) mice, using radioimmunoassay and immunohistochemical methods. The total pancreatic content and concentration of SRIF was decreased in male KK mice compared to their male controls aged 12-18 weeks. These results were consistent with the immunohistochemical findings. Pancreatic glucagon concentration and number of glucagon-containing cells were also decreased in KK mice, but pancreatic insulin concentrations were increased in KK mice. On the other hand, NOD mice aged 12-38 weeks within 15 days after onset of diabetes had increased concentrations of pancreatic SRIF. The pancreatic islets in NOD mice were decreased both in number and in size and were characterized by lymphocyte infiltration. SRIF-containing cells occupied the major part of the endocrine cells of the islets. Insulin-containing cells significantly decreased in number, but the number of glucagon-containing cells was fairly well preserved. These results and previous work concerning obob and dbdb mice indicate a parallel relationship between pancreatic SRIF and glucagon. The pancreatic glucagon thus as well as the pancreatic insulin may be an important determinant of pancreatic SRIF concentration in these diabetic animals.