Fate and effects of the alpha-glucosidase inhibitor acarbose in humans. An intestinal slow-marker perfusion study.

The alpha-glucosidase inhibitor acarbose has been successfully used in diabetic patients to decrease the postprandial rise in blood glucose. The aim of the present experiments was to investigate the fate and effects of acarbose along the small intestine using a slow-marker perfusion technique. In 8 healthy volunteers, jejunal and ileal loads of acarbose, glucose, and total carbohydrates were determined following a liquid, 400-kcal formula meal containing either 200 mg of acarbose or placebo. Preprandial and postprandial plasma concentrations of glucose and several polypeptide hormones were determined. Recovery of acarbose during 4 h was 65% +/- 9% (mean +/- SEM) of ingested dose in the ileum but 94% +/- 9% in the jejunum, indicating that the compound was neither degraded nor absorbed by the intestine to a major degree. After acarbose administration, ileal loads of glucose and total carbohydrates were considerably higher, whereas postprandial plasma concentrations of glucose, insulin, and gastric inhibitory polypeptide were lower when compared with placebo. The retardation of carbohydrate digestion to be inferred from these findings is confirmed by significantly elevated plasma concentrations of enteroglucagon after acarbose administration compared with placebo administration.