Effect of octreotide on pancreatic endocrine function in partial pancreatectomy

Octreotide acetate (Sandostatin), a long-acting somatostatin analogue, has been demonstrated to inhibit pancreatic exocrine secretion. The effect of octreotide acetate on pancreatic endocrine function in patients undergoing pancreas surgery or pancreas transplantation has not been as well described, nor have the clinical implications been studied as systematically. This study was designed to investigate the effects of octreotide acetate on glucose metabolism and endocrine function in a partial pancreatectomized canine model, simulating reduced islet cell reserve. Serum levels of glucose, insulin, and glucagon were determined at intervals over 2 hr following an intravenous glucose tolerance test (0.5 g/kg intravenous bolus of 50% glucose) in: normal animals (Group A, n = 5), normal animals pretreated with an intravenous bolus of 400 micrograms of octreotide acetate (Group B, n = 5), partial pancreatectomized animals (Group C, n = 5), and partial pancreatectomized animals pretreated with an intravenous bolus of 400 micrograms of octreotide acetate (Group D, n = 5). Peak glucose concentration was significantly increased in Group D when compared to Group C (Group C = 304.2 +/- 13.5 mg/dl vs Group D = 353.2 +/- 12.9 mg/dl, P < 0.05), indicating an impairment of glucose metabolism by octreotide. In addition, octreotide significantly decreased peak insulin release in the partial pancreatectomy groups (Group C = 129 +/- 12.9 micro U/ml vs Group D = 47.5 +/- 6.8 micro U/ml, P < 0.05). There were no significant differences in the rate of glucose utilization or glucagon concentrations among the groups. These results demonstrate that octreotide does result in insulin suppression, with a resultant increase in stimulated glucose concentrations, in a canine model of reduced islet cell mass. Further studies are required to determine the mechanism of action of octreotide on endocrine function in the setting of pancreas transplant.