Gastric acid secretion and gut hormone release in patients undergoing pancreaticoduodenectomy

The changes in gastric acid secretion and gut hormone release were investigated in 11 patients who underwent pancreaticoduodenectomy. The amount of acid output showed normoacidity before surgery and hypoacidity after surgery. No peptic ulcers were detectable after surgery. Plasma gastrin levels were markedly reduced after surgery both in the fasting state and after a test meal loading. Although fasting plasma levels of both gastric inhibitory polypeptide (GIP) and insulin after surgery were close to those before surgery, the response of these hormones to the meal was significantly reduced after surgery. On the other hand, blood glucose concentrations increased gradually after feeding, and the elevation was greatly prolonged after surgery compared with preoperative levels. From these results, it is concluded that peptic ulcer will not occur if subtotal gastrectomy is performed during Whipple's procedure. It is presumed that the diminished release of gut hormones such as gastrin, GIP, and insulin was due to the massive resection of the distal stomach, the upper small intestine, and the head of the pancreas and to the diversion of the stream of food from the duodenum to the jejunum. It is also assumed that the glucose-dependent insulinotropic action of GIP would be impaired by the procedure.