Inhibition of intestinal α-glucosidase activity and postprandial hyperglycemia by α-glucosidase inhibitors in fa/fa rats

The effect of α-glucosidase inhibitors (acarbose and miglitol) on the digestion of various sources of starch at different ages has been studied in fa/fa rats. These rats, become obese at 6 months of age and demonstrate impaired glucose tolerance accompanied by hyperinsulinemia. Acarbose and miglitol dramatically decreased the postprandial glucose level following potato, corn and rice loading. These drugs were less effective in 10-month old rats but to the extent which differed with the starch used. The percent inhibition achieved by acarbose from 2 to 10 months of age dropped from 68 27%; 78 to 44% and 62 to 50% for potato, corn and rice, respectively; the corresponding figures with miglitol was: 63 to 11%, 47 to 40% and 38 to 42%. These data, together with in vitro results, using the inverted sac technique, indicate that acarbose is more potent than miglitol. The effect of α-glucosidase inhibitors on starch digestion may depend on the nutrient composition and their interaction among nutrients in foods. Both drugs blunted the rise in glucose levels following starch ingestion in fa/fa rats. They may be a useful adjuvant in the treatment of obesity coupled with impaired glucose level. The effect of both drugs on carbohydrate digestion, mainly in old age, requires further elucidation.