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Glutamine transport by human intestinal basolateral membrane vesicle
1Department of Pediatrics, Vanderbilt University, Nashville, TN.
The American Journal of Clinical Nutrition
|April 1, 1990
Summary
This study details glutamine transport across human intestinal cells. It reveals two key transport systems, one sodium-dependent and one independent, crucial for amino acid uptake.
Area of Science:
- Physiology
- Biochemistry
- Molecular Biology
Background:
- Glutamine is a vital amino acid for human health.
- Understanding its transport is crucial for nutrient absorption.
- Basolateral membrane transport in human enterocytes remains incompletely characterized.
Purpose of the Study:
- To characterize glutamine transport across human basolateral membrane vesicles.
- To elucidate the kinetic properties and mechanisms of glutamine uptake.
- To identify factors influencing glutamine transport.
Main Methods:
- Utilized a well-validated technique for basolateral membrane vesicle preparation.
- Measured glutamine uptake under varying pH, temperature, and ion gradients (sodium and potassium).
- Performed kinetic analysis to determine Vmax and Km values for transport processes.
Main Results:
- Glutamine uptake is temperature- and pH-dependent, optimal at pH 7.5.
- Transport occurs via both sodium-dependent and sodium-independent carrier-mediated processes.
- Kinetic analysis revealed distinct Vmax and Km values for each transport system.
- Sodium-dependent transport is electrogenic, while sodium-independent transport is electroneutral.
- Neutral amino acids inhibit both transport mechanisms.
Conclusions:
- Confirms the presence of carrier-mediated glutamine uptake at the human enterocyte basolateral membrane.
- Characterizes two distinct glutamine transport systems with different kinetic and mechanistic properties.
- Provides foundational data for understanding amino acid absorption and metabolic regulation in the human gut.