Surgical alterations of the pancreas and insulin-independent glucose disposal

Systemic drainage of pancreatic venous effluent and denervation of the pancreas that follows pancreatic transplantation has been shown to alter postoperative glucose disposal despite elevated levels of peripheral insulin in response to a glucose challenge. Since an appreciable fraction of postprandial glucose disposal takes place in the absence of insulin (insulin-independent glucose disposal--IIGD), we have investigated potential changes in this aspect of carbohydrate metabolism before and after bladder-drained pancreatic auto-transplantation (PAT/B) as well as partial pancreatectomy (PPx). The hyperglycemic clamp protocol with a background infusion of somatostatin was performed on control (PREOP) dogs as well as PAT/B and PPx animals. The rate of glucose disposal (M Value) during the period of hypoinsulinemia induced by Somatostatin (SST) was measured and reported. Whereas glucose disposal during steady state hyperglycemia was significantly diminished for both PPx and PAT/B in the absence of SST, IIGD was unaltered across all three groups studied. We therefore conclude that surgical alteration of the pancreas results in abnormal glucose disposal during steady state hyperglycemia despite apparently normal to supranormal levels of peripheral insulin, and that alterations in IIGD are not responsible for these differences.