Character of a wheat amylase inhibitor preparation and effects on fasting human pancreaticobiliary secretions and hormones

Background & Aims: Amylase inhibition induces carbohydrate tolerance, satiety, and weight loss and prolongs gastric emptying, effects that may be useful in the treatment of obesity and non-insulin-dependent diabetes mellitus, The aim of this study was to determine (1) purity of a wheat amylase inhibitor preparation, (2) intraduodenal concentration of the wheat amylase inhibitor preparation that inhibits >90% amylase activity (which causes carbohydrate malabsorption), and (3) if the inhibitor alters pancreaticobiliary secretions or intraluminal pH, Methods: High-performance liquid chromatography followed by electrophoresis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis were used for characterization, Groups of 3 subjects received intraduodenal infusions of 3.0, 4.5, or 6.0 mg/mL of the inhibitor for 90 minutes during the middle of a 270-minute essential amino acid solution infusion (which stimulates 50% maximal pancreatic enzyme secretion), Pancreatic enzyme and bile acid delivery to the duodenum were measured for a 270-minute period. Results: The inhibitor is 96% protein, 59% containing 0.19, 0.28, 0.38, and 0.53 inhibitors. The 0.38 inhibitor has the most antipancreatic alpha-amylase activity, The inhibitor reduced amylase activity in the duodenum dose dependently (r = 0.7; P = 0.04); >4 mg/mL inhibited >90% amylase activity but did not affect delivery of other enzymes or bile acids to the duodenum or gastric or duodenal pH. Conclusions: The preparation has a high protein purity and a high specific activity against alpha-amylase activity and effectively inhibits human pancreatic amylase activity secreted into the duodenum.