Related Experiment Videos
Creatine transport in brush-border membrane vesicles isolated from rat kidney cortex
Marta García-Delgado1, María J Peral1, Mercedes Cano1
1Department of Animal Physiology and Biology, Facultad de Farmacia, Universidad de Sevilla, Sevilla, Spain.
Journal of the American Society of Nephrology : JASN
|August 24, 2001
Summary
The kidney reabsorbs creatine using an active transport system in the renal cortex. This process involves a specific cotransporter that requires sodium and chloride ions.
Area of Science:
- Nephrology
- Molecular Biology
- Biochemistry
Background:
- The kidney's role in salvaging creatine from urine is crucial for maintaining body creatine levels.
- The specific molecular mechanisms underlying renal creatine reabsorption have remained largely uncharacterized.
Purpose of the Study:
- To investigate and characterize the creatine transport mechanism in the brush-border membrane of rat renal cortical tubules.
Main Methods:
- Isolation of brush-border membrane vesicles from rat renal cortex.
- Measurement of creatine uptake under various ionic conditions and membrane potentials.
- Kinetic analysis and inhibition studies using various compounds.
Main Results:
- Creatine transport is an active, Na(+)- and Cl(-)-dependent process, indicated by overshoot phenomenon and gradient stimulation.
- The transport is electrogenic, stimulated by an inside-negative K(+) diffusion potential.
- Stoichiometric analysis suggests a 2 Na(+):1 Cl(-):1 creatine cotransporter.
- High-affinity transport (K(m) = 15 microM) with specific inhibition patterns was observed.
Conclusions:
- The apical membrane of renal cortical tubules possesses an active, high-affinity, electrogenic cotransporter for creatine.
- This transporter likely moves 2 Na(+) and 1 Cl(-) ions along with 1 creatine molecule.