title: Effects of graded alpha-glucosidase inhibition on sugar absorption in vivo.
abstract: The effect of inhibition of disaccharidases on the degree of absorption of glucose, lactose, and sucrose was examined utilizing an in vivo model in the rat. Acarbose, a competitive alpha-glucosidase inhibitor was utilized to selectively inhibit small intestinal mucosal enzymes. Adult rats (250-350 g body weight) were the subjects of intraduodenal bolus infusion experiments with either sugar alone or sugar plus acarbose. All sugars were infused at a dose of 0.5 g/kg body weight. Portal venous blood glucose was determined at 30-min intervals from 0 to 150 min. Glucose (monosaccharide) and lactose (beta-galactoside) absorption were not altered by the presence of acarbose. In contrast, sucrose (alpha-glucosidase) absorption was significantly diminished in the presence of acarbose. Sucrose absorption in the presence of increasing acarbose doses (0.7-5.6 mg/kg body weight) was depressed in a dose-dependent fashion. Linear regression analysis revealed a high degree of correlation between residual sucrase activity and area under blood glucose curve (r = 0.9837). Similar degrees of correlation were found between acarbose dose and area under blood glucose curve (r = -0.9322), and between residual sucrase activity and acarbose dose (r = -0.9695). These data confirm that acarbose is a selective alpha-glucosidase inhibitor that does not affect monosaccharidase transport. In the presence of acarbose, alpha-glucosidase absorption is diminished in a dose-dependent fashion. Postprandial glucose rise following an alpha-glucosidase meal seems to be determined, in the presence of graded acarbose inhibition, by residual mucosal alpha-glucosidase activity.
authors.affiliation: International Institute for Infant Nutrition and Gastrointestinal Disease, Children's Hospital of Buffalo.
authors.forename: H
authors.initials: H
authors.lastname: Madariaga
authors.forename: P C
authors.initials: PC
authors.lastname: Lee
authors.forename: L A
authors.initials: LA
authors.lastname: Heitlinger
authors.forename: E
authors.initials: E
authors.lastname: Lebenthal
mesh_terms: D020909:Acarbose; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000008:administration & dosage / Q000378:metabolism*; D065089:Glycoside Hydrolase Inhibitors; D006868:Hydrolysis; D007408:Intestinal Absorption / Q000187:drug effects; D007413:Intestinal Mucosa / Q000201:enzymology / Q000378:metabolism; D007785:Lactose / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012044:Regression Analysis; D013395:Sucrose / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000097:blood / Q000378:metabolism*; D013997:Time Factors; D014312:Trisaccharides / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D001786:Blood Glucose; D065089:Glycoside Hydrolase Inhibitors; D014312:Trisaccharides; D013395:Sucrose; D005947:Glucose; D007785:Lactose; D020909:Acarbose