Effect of ventromedial hypothalamic lesions on the secretion of somatostatin, insulin, and glucagon by the perfused rat pancreas

Abstract

Somatostatin, insulin, and glucagon secretion by the perfused pancreas were studied in adult female rats 10 days after ventromedial hypothalamic (VMH) lesions and in sham operated controls to assess the role of their hypothalamic control. Insulin secretion was significantly greater in VMH-lesioned rats both under basal conditions and after stimulation by theophylline and arginine plus theophylline. Basal glucagon secretion was greater in VMH-lesioned rats as was the glucagon response to theophylline alone and in combination with arginine. Basal somatostatin secretion with similar in VMH and control rats but somatostatin secretion induced by theophylline and by arginine plus theophylline was significantly increased in VMH-lesioned rats. Both the pancreatic content and concentration of somatostatin were increased in VMH-lesioned rats. These results indicate the presence of hyperresponsiveness of A, B, and D cells following VMH destruction and provide new evidence for a role of the hypothalamus in the regulation of pancreatic somatostatin secretion.