|
|
||||||||
AJP - Gastrointestinal and Liver Physiology, Vol 256, Issue 1 240-G245, Copyright © 1989 by American Physiological Society
ARTICLES |
H. M. Said, K. Van Voorhis, F. K. Ghishan, N. Abumurad, W. Nylander and R. Redha
Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Transport of glutamine (Gln) across the brush-border membrane of the human intestine was examined using the brush-border membrane vesicle (BBMV) technique. Osmolarity and temperature studies indicate that the uptake of Gln by BBMV is mostly the result of transport of the substrate into the intravesicular space. Transport of Gln was Na+ gradient dependent (out greater than in) with a distinct "overshoot" phenomenon. Initial rate of transport of Gln as a function of concentration was saturable both in the presence and absence of a Na+ gradient (out greater than in). Apparent Km of 1.86 and 1.36 mM and Vmax of 1,906 and 637 pmol.mg protein-1 . 7 s-1 were calculated for the Na+-dependent and the Na+-independent transport processes of Gln, respectively. The transport of [3H]Gln (0.58 mM) by the Na+-dependent and the Na+-independent processes was severely inhibited by the addition to the incubation medium of serine, asparagine, and unlabeled Gln. Inducing a relatively negative intravesicular compartment with the use of valinomycin and an outwardly directed K+ gradient or with the use of anions of different lipid permeabilities indicates that Gln transport by the Na+-dependent process is electrogenic in nature. Transport of Gln by the Na+-independent process, however, appeared to be electroneutral in nature. These results demonstrate the existence of two carrier-mediated transport processes for Gln in the human intestinal BBMV, one is Na+ dependent and the other is Na+ independent. Furthermore, the results suggest that Gln transport by the Na+-dependent process probably occurs by a Gln-Na+ cotransport mechanism.
This article has been cited by other articles:
![]() |
M. Coeffier, B. Hecketsweiler, P. Hecketsweiler, and P. Dechelotte Effect of glutamine on water and sodium absorption in human jejunum at baseline and during PGE1-induced secretion J Appl Physiol, June 1, 2005; 98(6): 2163 - 2168. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. G. Boelens, R. J. Nijveldt, A. P. J. Houdijk, S. Meijer, and P. A. M. van Leeuwen Glutamine Alimentation in Catabolic State J. Nutr., September 1, 2001; 131(9): 2569S - 2577. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. Crenn, F. Thuillier, B. Rakatoambinina, M. Rongier, D. Darmaun, and B. Messing Duodenal vs. gastric administration of labeled leucine for the study of splanchnic metabolism in humans J Appl Physiol, August 1, 2000; 89(2): 573 - 580. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |