The effects of an alpha-glucoside hydrolase inhibitor on glycemia and the absorption of sucrose in man determined using a tracer method.

Acarbose, an alpha-glucosidase inhibitor, lowers the glycemic excursion following the ingestion of carbohydrates, in particular, sucrose. This was confirmed with increasing doses of acarbose (0, 50, and 100 mg) and the causes investigated. The absorption of the glucose moiety of sucrose was determined from plasma tracer concentrations when overnight-fasted normal subjects received a 100-g oral sucrose load labeled with sucrose [(1-14C]glucose and a simultaneous intravenous infusion of [3-3H]glucose. As the dose of acarbose given with the sucrose load was increased from 0 to 100 mg, the percentage of the load appearing in the peripheral circulation decreased from 90% to 62%. Malabsorption was confirmed by the appearance of breath hydrogen. Simultaneously, absorption time increased from 243 to 411 min. Maximal glycemic excursions were therefore lowered from 64 to 31 mg/dl. The plasma concentrations of gastric inhibitory polypeptide and insulin decreased with the acarbose dose so that the fractional disappearance rate of glucose also decreased. However, the concentrations of glucagon-like immunoreactivity (GLI) rose, confirming the ileal appearance of malabsorbed sucrose.