Related Experiment Videos
Dipeptide-induced Cl- secretion in proximal tubule cells
1Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, USA.
The American Journal of Physiology
|December 31, 1997
Summary
Acidic dipeptides stimulate anion secretion in kidney proximal tubule cells, independent of the PEPT2 transporter. This suggests a novel chloride secretion pathway activated by these peptides.
Area of Science:
- Nephrology
- Cell Physiology
- Molecular Transport
Background:
- The renal PEPT2 transporter plays a role in peptide uptake in proximal tubule cells.
- The physiological consequences of acidic dipeptide interaction with proximal tubule cells are not fully understood.
Purpose of the Study:
- To investigate the effects of acidic dipeptides on ion transport in proximal tubule cells.
- To characterize the mechanism of anion secretion stimulated by acidic dipeptides.
Main Methods:
- Utilized immortalized proximal tubule cell lines from rat and human origins.
- Measured transepithelial electrical current and conductance.
- Investigated ion dependency (Na+, Cl-) and pH effects.
- Examined inhibition by specific channel blockers.
Main Results:
- Acidic dipeptides, like Ala-Asp, induced a transient secretory anion current and conductance increase.
- This effect was observed across multiple proximal tubule cell lines, indicating a general characteristic.
- The current was Na+-independent and involved Cl- secretion via a non-cystic fibrosis transmembrane conductance regulator (CFTR) type channel.
- Ala-Asp also caused intracellular acidification, suggesting co-transport with H+.
Conclusions:
- Acidic dipeptides activate a distinct Cl- secretory pathway in proximal tubule cells.
- This pathway is separate from the PEPT2 transporter and likely involves a novel Cl- conductance.
- Acidic dipeptides may also be substrates for an H+-peptide cotransporter.