Related Experiment Video
Updated: Aug 10, 2026
09:42
Deriving the Time Course of Glutamate Clearance with a Deconvolution Analysis of Astrocytic Transporter Currents
Published on: August 7, 2013
Glutamate transport and renal function
1Department of Molecular Physiology, Louisiana State University Medical Center, Shreveport, Louisiana 71130, USA. twelbo@lsunc.edu
The American Journal of Physiology
|October 12, 1999
Summary
Brush border enzymes and the EAAC1 transporter generate extracellular glutamate in kidney tubules. This signals changes in cell metabolism, permeability, and urine acidity, with GLT1 playing distinct roles.
Area of Science:
- Nephrology
- Molecular Biology
- Biochemistry
Background:
- The kidney proximal tubule plays a crucial role in regulating solute and water balance.
- Glutamate transport and metabolism are vital for various physiological processes within the kidney.
- Understanding the specific roles of different glutamate transporters is essential for comprehending kidney function.
Purpose of the Study:
- To investigate the functional unit of brush border gamma-glutamyltransferase-glutaminase and the EAAC1 transporter in proximal tubules.
- To elucidate the role of extracellular glutamate generated by this unit in modulating intracellular metabolism and kidney function.
- To explore the implications of the presence of GLT1 on the antiluminal surface.
Main Methods:
- Biochemical assays to measure gamma-glutamyltransferase-glutaminase activity.
- Functional studies of the EAAC1 glutamate transporter in kidney proximal tubule cells.
- Analysis of intracellular glutamine/glutamate metabolism.
- Assessment of paracellular permeability and urinary acidification.
Main Results:
- Brush border gamma-glutamyltransferase-glutaminase activity and EAAC1 transporter function collaboratively.
- This unit generates and transports extracellular glutamate into proximal tubules.
- Extracellular glutamate acts as a signal influencing intracellular glutamine/glutamate metabolism, paracellular permeability, and urinary acidification.
- GLT1 is present on the antiluminal tubule surface, suggesting specialized functions.
Conclusions:
- The coordinated action of brush border enzymes and EAAC1 is critical for regulating proximal tubule physiology.
- Extracellular glutamate serves as a key signaling molecule in the kidney.
- Distinct roles for EAAC1 and GLT1 in kidney function and disease are proposed.
Related Concept Videos
01:27Glucose Transporters
Glucose transporters facilitate the transport of glucose across the cell membrane. In addition to glucose, some glucose transporters can also aid the movement of other hexoses such as fructose, mannose, and galactose.
Facilitated diffusion-glucose transporters (GLUTs) are encoded by the solute-linked carrier (SLC) family 2, subfamily A gene family, or SLC2A. The 14 GLUT protein members are distributed into three classes:
Facilitated diffusion-glucose transporters (GLUTs) are encoded by the solute-linked carrier (SLC) family 2, subfamily A gene family, or SLC2A. The 14 GLUT protein members are distributed into three classes:
01:15Drug Elimination by Renal Route: Tubular Secretion
Once the process of glomerular filtration is completed, blood carrying unfiltered drug molecules traverses through efferent arterioles and makes its way into the peritubular capillaries in the proximal tubule. A variety of carriers play a pivotal role in actively secreting drugs from these peritubular capillaries into the tubular fluid. The organic anion transporter transfers acidic drugs, against an electrochemical gradient, from the peritubular capillaries into the renal tubule cells and...
01:14Antiepileptic Drugs: Glutamate Antagonists
Glutamate is a fundamental neurotransmitter in the central nervous system, playing a vital role in neuronal communication and various cognitive processes. Glutamate stands as the principal excitatory neurotransmitter in the brain. Its presence is crucial for the communication between neurons, underpinning essential processes such as synaptic transmission, neuronal excitability, and plasticity. These functions are vital for higher-order cognitive processes, including learning and memory. The...
01:25Renal Drug Excretion: Tubular Reabsorption
Tubular reabsorption, a process occurring post-glomerular filtration of drugs in the renal tubule, is a critical determinant of drug half-life. During the process of renal excretion, as the glomerular filtrate progresses to the distal convoluted tubule (DCT), drugs that are highly permeable, lipophilic, and nonionized undergo passive reabsorption from the tubular fluid into the surrounding peritubular capillaries. This reabsorption process restricts their elimination through the kidneys. This...
01:28Renal Drug Excretion: Tubular Secretion
Active tubular secretion is a robust, energy-demanding process that utilizes carrier systems to transport drugs into renal tubules. The active renal secretion systems include the organic anion transporter (OAT) for weak acids and the organic cation transporter (OCT) for weak bases. Structurally similar drugs can compete for the same transporter, potentially leading to drug accumulation and toxicity. However, this principle can be exploited therapeutically. One example is probenecid (Probalan),...
01:25Drug Dosing in Renal Diseases: Measurement of Glomerular Filtration Rate
The glomerular filtration rate (GFR) is a critical indicator of kidney health, reflecting how well the kidneys filter blood. Changes in GFR can signal potential kidney impairment, necessitating accurate measurement methods to monitor kidney function effectively.Various molecules can serve as markers for GFR measurement, with the ideal marker meeting several specific criteria. It must freely filter at the glomerulus, avoid reabsorption or secretion by the renal tubules, remain unmetabolized, not...