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Calcitonin stimulates H+ secretion in rat kidney intercalated cells
E Siga1, P Houillier, B Mandon
1Service de Biologie Cellulaire, Centre d'Etudes de Saclay, Commissariatà l'Energie Atomique, Gif-sur-Yuette, France.
The American Journal of Physiology
|December 1, 1996
Summary
Calcitonin (CT) stimulates proton (H+) secretion in rat kidney collecting ducts, likely via alpha-intercalated cells. Isoproterenol (ISO) stimulates bicarbonate (HCO3-) secretion, likely via beta-intercalated cells.
Area of Science:
- Nephrology
- Renal Physiology
- Cell Biology
Background:
- Calcitonin (CT) is known to modulate functions of intercalated cells (IC) in the rat cortical collecting duct (CCD).
- Specific cellular mechanisms and pathways regulated by CT in the CCD remain incompletely understood.
Purpose of the Study:
- To elucidate the specific function regulated by calcitonin (CT) in the rat cortical collecting duct (CCD).
- To differentiate the cellular actions of CT from those of isoproterenol (ISO) in the CCD.
Main Methods:
- In vitro perfusion of rat CCDs.
- Measurement of total CO2 net fluxes (JtCO2) and transepithelial voltage (Vt).
- Pharmacological manipulation of bicarbonate (HCO3-) and proton (H+) secretion pathways.
Main Results:
- Calcitonin (CT) induced significant CO2 reabsorption, an effect potentiated in acid-loaded rats.
- CT's effect on JtCO2 and Vt was dependent on intact H+ secretion pathways.
- Isoproterenol (ISO) stimulated HCO3- secretion and Na(+)-dependent Vt, distinct from CT's actions.
Conclusions:
- Calcitonin (CT) stimulates proton (H+) secretion, likely mediated by alpha-intercalated (alpha-IC) cells in the rat CCD.
- Isoproterenol (ISO) stimulates bicarbonate (HCO3-) secretion, likely mediated by beta-intercalated (beta-IC) cells in the rat CCD.
- CT and ISO exert distinct regulatory effects on ion transport in the rat CCD via different IC subtypes.