title: Transport of glucose polymer-derived glucose by rabbit jejunum.
abstract: Mechanisms for the assimilation of glucose polymers have been inferred from perfusion studies. To further define these mechanisms, the results of measurements of unidirectional glucose fluxes across short-circuited rabbit jejunal segments in vitro are reported. Glucose polymer-stimulated short-circuit current was similar to that of glucose [19 +/- 6.0 microA/cm2 (n = 7) and 26 +/- 5.7 microA/cm2 (n = 13), respectively] and was inhibited by both acarbose and phlorizin. Acarbose, an alpha-glucosidase inhibitor with no effects of glucose transport, was used to uncouple digestion from absorption. Mucosal-to-serosal flux of glucose polymer-derived glucose was lower than that of an equal weight/volume of glucose [124 +/- 62 nmol.h-1.cm-2 (n = 4) vs. 452 +/- 121 nmol.h-1.cm-2 (n = 6); P less than 0.05] and was inhibited by both phlorizin and acarbose. No glucose polymers were detected in the serosal bath solutions by thin-layer chromatography. It is concluded that glucose polymer-derived glucose is transported by a phlorizin-inhibitable process at a rate slower than that of free glucose, a finding that suggests that hydrolysis limits glucose polymer assimilation.
authors.affiliation: Department of Pediatrics, Ohio State University, Columbus.
authors.forename: L A
authors.initials: LA
authors.lastname: Heitlinger
authors.forename: H R
authors.initials: HR
authors.lastname: Sloan
authors.forename: D R
authors.initials: DR
authors.lastname: DeVore
authors.forename: P C
authors.initials: PC
authors.lastname: Lee
authors.forename: E
authors.initials: E
authors.lastname: Lebenthal
authors.forename: M E
authors.initials: ME
authors.lastname: Duffey
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001693:Biological Transport, Active; D002352:Carrier Proteins / Q000378:metabolism; D002855:Chromatography, Thin Layer; D004594:Electrophysiology; D005936:Glucans / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D006868:Hydrolysis; D066298:In Vitro Techniques; D007583:Jejunum / Q000378:metabolism*; D008297:Male; D011817:Rabbits
chemical_list: D002352:Carrier Proteins; D005936:Glucans; D005947:Glucose