Premium
Effect of systemic pH, PCO 2 and bicarbonate concentration on biliary bicarbonate secretion in the rat
Author(s) -
Corbic Michèle,
Muñoz Cristina,
Dumont Micheline,
Couët Ghislaine De,
Erlinger Serge
Publication year - 1985
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.1840050412
Subject(s) - bicarbonate , medicine , respiratory alkalosis , endocrinology , metabolic alkalosis , metabolic acidosis , alkalosis , acetazolamide , chemistry , acidosis , secretion , pco2 , carbonic anhydrase , net acid excretion , biochemistry , excretion , enzyme
The effect of acute metabolic or respiratory acid‐base disturbances on biliary bicarbonate secretion was examined in bile fistula rats. Animals were infused with ursodeoxycholate at a rate that stimulates bicarbonate secretion (1 μmole · min −1 · 100 gm −1 ), in control conditions and during acute acid‐base disturbances. Metabolic acidosis or alkalosis were induced by HCl or NaHCO 3 infusions, and respiratory acidosis or alkalosis were created respectively by adding CO 2 to the inspired gas or by hyperventilation in artificially ventilated animals. Biliary bicarbonate concentration was always higher than plasma bicarbonate concentration. During metabolic disturbances, changing the plasma bicarbonate concentration from 9.2 to 30.2 m M stimulated biliary bicarbonate secretion by 113%. During respiratory disturbances, changing the plasma PCO 2 from 25.5 to 59.8 mm Hg also increased biliary bicarbonate secretion by 89%. Biliary bicarbonate output was thus independent of plasma pH. When all animals were considered, bile flow was positively correlated with biliary bicarbonate concentration (r = 0.71, p < 0.001). Acetazolamide significantly decreased ursodeoxycholate‐induced bile flow and bicarbonate secretion by 20 and 22%, respectively. These results support the hypothesis that there is a relationship between ursodeoxycholate‐induced bicarbonate secretion and bile flow. They are also consistent with the view that ursodeoxycholate‐stimulated biliary bicarbonate secretion in the rat is strongly affected by plasma bicarbonate and PCO 2 , but not by plasma pH, and involves carbonic anhydrase.