Reduced insulin secretion by subtotal pancreatectomy: preservation of insulin sensitivity and glucose tolerance in postoperative patients.

This study investigated insulin sensitivity and glucose tolerance after subtotal pancreatectomy for carcinoma of the head of the pancreas. Twelve consecutive, non-diabetic patients were studied after potentially curative surgery at which the distal pancreas was stapled off, leaving approximately 15% of the pancreas in situ. Brief infusions of insulin (10 mU kg-1) and glucose (25 g) were given before and 4 days after operation. Postoperatively, blood glucose levels remained unchanged, whereas fasting levels of insulin. C-peptide, and pancreatic glucagon were decreased, although significantly (p less than 0.01) only for glucagon. The early and late phases of the insulin and C-peptide responses to glucose were severely reduced. Notably, the hypoglycemic action of insulin and the glucose tolerance were similar to those observed before operation. It is concluded that an acute reduction in pancreatic mass does not impair insulin action or glucose tolerance shortly after surgery. This contrasts with the insulin resistance and glucose intolerance seen shortly after pancreas-preserving intra-abdominal procedures of similar size. It is suggested that the decrease in glucagon levels is at least partly responsible for the preservation of insulin action after subtotal pancreatectomy.