Abstract
Because secretin tests have been used to establish the Zollinger-Ellison (Z-E) diagnosis, the effects of i.v. infusion (1 CU/kg/h) or injection (1 CU/kg) of secretin on serum concentrations of gastrin in hypersecretors with a verified Z-E diagnosis (n = 25) or duodenal ulcer disease (n = 19) were compared. Serum concentrations of gastrin rose in both groups. The gastrin response was significantly higher in Z-E patients after the injection only, but values were overlapping and some Z-E patients did not respond. Thus secretin does not have inverse action in Z-E patients compared with ordinary ulcer disease, and a ‘positive’ test is neither a sufficient nor a necessary criterion for the Z-E diagnosis. The diagnostic value was not augmented by fractionation of serum gastrin into the various components. Pre- and post-operative studies showed that total gastrectomy did not influence either the gastrin response to secretin (n = 5) or the serum gastrin level (n = 8). It has been speculated that secretin plays a pathogenetic role in the Z-E syndrome, because of an inverse action with stimulation of gastrin release and acid secretion. Although serum concentrations of secretin were higher in fasting unoperated and gastrectomized Z-E patients (5.6 ± 0.75, n = 11; 2.2 ± 0.8, n = 5 pmol/l) than in normals (1.4 ± 0.2, n = 74), our study does not support the proposition that release of secretin by acid entering the duodenum should drive the gastrin release from gastrinomas because: 1) exogenous secretin often failed to raise serum concentrations of gastrin, although the resulting concentrations of serum secretin were far above those normally seen in Z-E patients, and 2) serum concentrations of gastrin did not decrease after total gastrectomy.