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Apical acidification by rabbit papillary surface epithelium
P S Chandhoke1, R K Packer, M A Knepper
1Laboratory of Kidney and Electrolyte Metabolism, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892.
The American Journal of Physiology
|April 1, 1990
Summary
The rabbit papillary surface epithelium (PSE) acidifies urine, independent of oxygen but dependent on glycolysis. This process may influence kidney stone formation.
Area of Science:
- Renal Physiology
- Cell Biology
- Biochemistry
Background:
- The papillary surface epithelium (PSE) lines the renal papilla and faces the urinary space.
- Understanding acid-base transport mechanisms in the kidney is crucial for renal physiology.
Purpose of the Study:
- To investigate the capacity and mechanisms of acid-base transport in the rabbit papillary surface epithelium (PSE).
Main Methods:
- Dissection of rabbit PSE and mounting in a Ussing chamber.
- Monitoring pH changes in the apical bathing solution to assess acidification rates.
- Utilizing metabolic inhibitors (iodoacetate, antimycin A) and altered solution compositions (nitrogen, oxygen, ion removal) to probe transport mechanisms.
Main Results:
- The PSE significantly acidifies the apical solution.
- Acidification is independent of oxidative metabolism but dependent on glycolysis.
- Lactate secretion accounts for only a minor portion of the total acid secretion.
- Apical acidification persists despite removal of sodium/potassium or addition of N-ethylmaleimide.
Conclusions:
- The rabbit PSE actively acidifies the apical solution, primarily via glycolysis.
- While its contribution to overall acid excretion is limited by surface area, the PSE can locally alter urine pH.
- The PSE has the potential to influence the formation of renal stones within pelvic recesses.