Changes in pancreatic somatostatin content in spontaneously diabetic mice, as determined by radioimmunoassay and immunohistochemical methods.
A specific RIA for somatostatin (SRIF) was used to determine the SRIF content of the pancreas and hypothalamus in spontaneously diabetic C57BL/KsJ dbdb and C57BL/6J obob mice. In addition, SRIF- and glucagon-containing cells were examined in the pancreatic islets with an immunohistochemical technique. In dbdb mice, immunoassayable pancreatic SRIF content was increased, as was the number of SRIF- or glucagon-containing cells. In obob mice, immunoassayable pancreatic SRIF content was also increased, but no increase was noted in the number of SRIF- or glucagon-containing cells. The hypothalamic SRIF content of either strain was not different from that of controls. These results regarding pancreatic SRIF content were in accord with some but not all previous reports. These differences may be related to the age of the mice or to the conditions in which they were bred. The pancreatic SRIF increase in both dbdb and obob mice may be attributable to hyperglucagonemia, hyperglycemia, or a decrease in insulin action. Further work is necessary to clearly delineate the mechanism.