Glutamine transport by human intestinal basolateral membrane vesicle.

Ghishan FK, Arab N, Bulus N, Said H, Pietsch J, Abumrad N
Am J Clin Nutr. 1990 51 (4): 612-6

PMID: 2321568 · DOI:10.1093/ajcn/51.4.612

This study characterizes for the first time, by use of a well-validated technique, glutamine transport across human basolateral membrane vesicles. Glutamine transport represented uptake into an osmotically active intravesicular space without significant metabolism. Glutamine uptake was temperature- and pH-dependent with maximal uptake at pH 7.5, and it was mediated by sodium-dependent and -independent processes. The initial rate of uptake was linear up to 20 s, as depicted by the formula gamma (nmol/mg protein) = 0.0009 X (s) - 0.0011 (r = 0.99). Kinetic analysis of glutamine uptake at concentrations between 0.01 and 0.3 mmol/L at 5 s under sodium and potassium gradients showed a maximal transport capacity (Vmax) of 0.39 +/- 0.04 and 0.21 +/- 0.02 nmol.mg protein-1.5 s-1 for sodium-dependent and -independent processes, respectively (p less than 0.01). Km values were 0.17 +/- 0.04 and 0.06 +/- 0.2 mmol/L, respectively (p less than 0.05). Glutamine uptake under the sodium-gradient condition was electrogenic whereas under the potassium-gradient it was electroneutral. Neutral amino acids inhibited both sodium-dependent and -independent processes. This study confirms and characterizes the presence of carrier-mediated glutamine uptake at the basolateral membranes of human enterocytes.

MeSH Terms (13)

Basement Membrane Biological Transport Glutamine Humans Hydrogen-Ion Concentration Intestinal Mucosa Kinetics Membrane Potentials Microvilli Osmolar Concentration Potassium Sodium Temperature

Connections (1)

This publication is referenced by other Labnodes entities:

Links