HOMEPRODUCTSCOMPANYCONTACTFAQResearchDictionaryPharmaSign Up FREE or Login

Cytosolic pH regulation in perfused rat liver: role of intracellular bicarbonate production.

Abstract
The contribution of metabolic bicarbonate to cytosolic pH (pHcyto) regulation was studied on isolated perfused rat liver using phosphorus-31 NMR spectroscopy. Removal of external HCO3- decreased proton efflux from 18.6+/-5.0 to 1.64+/-0.29 micromol/min per g liver wet weight (w.w.) and pHcyto from 7.17+/-0.06 to 6.87+/-0.06. In the nominal absence of bicarbonate, inhibition of carbonic anhydrase by acetazolamide induced a further decrease of proton efflux of 0.69+/-0.26 micromol/min per g liver w.w. reflecting a reduction in metabolic CO2 hydration, and hence a decrease of H+ and HCO3- supplies. Even though 27% of the proton efflux was amiloride-sensitive under bicarbonate-free conditions, amiloride did not change pHcyto, revealing the contribution of additional regulatory processes. Indeed, pH regulation was affected by the combined use of 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS) and amiloride since pHcyto decreased by 0.16+/-0.05 and proton efflux by 0.60+/-0.14 micromol/min per g liver w.w. The data suggest that amiloride-sensitive or SITS-sensitive transport activities could achieve, by themselves, pHcyto regulation. The involvement of two mechanisms, most likely Na+/H+ antiport and Na+:HCO3 symport, was confirmed in the whole organ under intracellular and extracellular acidosis. The evidence of Na-dependent transport of HCO3- in the absence of exogenous bicarbonate implies that the amount of metabolic bicarbonate is sufficient to effectively participate to pHcyto regulation.
AuthorsG Vidal, T Durand, P Canioni, J L Gallis
JournalBiochimica et biophysica acta (Biochim Biophys Acta) Vol. 1425 Issue 1 Pg. 224-34 (Sep 16 1998) ISSN: 0006-3002 [Print] Netherlands
PMID9813342 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
Chemical References
  • Bicarbonates
  • 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid
  • Amiloride
  • Acetazolamide
Topics
  • 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid (pharmacology)
  • Acetazolamide (pharmacology)
  • Acidosis (metabolism)
  • Amiloride (pharmacology)
  • Animals
  • Bicarbonates (metabolism)
  • Cytosol (metabolism)
  • Homeostasis
  • Hydrogen-Ion Concentration
  • In Vitro Techniques
  • Intracellular Fluid (metabolism)
  • Liver (drug effects, metabolism)
  • Magnetic Resonance Spectroscopy
  • Male
  • Perfusion
  • Rats
  • Rats, Wistar

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research graph!


Choose Username:
Email:
Password:
Verify Password:
Enter Code Shown: