FFECT OF ACARBOSE ON IN VITRO INTESTINAL ABSORPTION of MONOSACCHARIDES IN DIABETIC RATS

Background – Acarbose is known to lower blood glucose concentration by functioning as an α-glucosidase inhibitor in the intestine. It is also suggested that acarbose may directly arrest the intestinal absorption of hexoses. The purpose of the present study was to further elucidate the normal intestinal absorption of hexoses and the effect of acarbose on the rate of intestinal absorption of monosaccharides in normal and streptozocin-induced diabetic rats. Methods – Segments of small intestine, as everted sacs, from normal and diabetic rats were incubated in solutions of various concentrations of monosaccharides, with and without acarbose, at 37ºC for 90 min and the sugar concentration was measured before and after incubation. Student’s t-test with p < 0.05 was used to compare the mean ± standard error of the mean values for intestinal absorption rates of various sugars in different groups of rats. Results – The optimum effective dose of most sugars for intestinal absorption was 100 mg/dL and the best inhibitory dose of acarbose was 1 mg/mL. The rate of intestinal absorption of glucose and galactose in the presence of acarbose was significantly reduced in both normal and diabetic rats, while fructose and sucrose absorption was not affected significantly by acarbose in diabetic rats. Mannose absorption was not affected significantly by acarbose. Conclusion – Acarbose directly arrested the intestinal absorption of most hexoses at different rates, probably due to different mechanisms involved in the intestinal absorption of monosaccharides.