Nor-ursodeoxycholic acid in hepatobiliary diseases: A narrative review

Figure 1 Effects of nor-ursodeoxycholic acid in the hepatobiliary system. Nor-ursodeoxycholic acid stimulates choleresis and bicarbonate secretion. An unconjugated fraction of nor-ursodeoxycholic acid is secreted into the canalicular biliary system and protonated by hydrogen ions. Hydrogen is generated from carbonic acid, which is synthesised from the hydration of luminal carbon dioxide by carbonic anhydrase. Protonated bile acids are absorbed and generate bicarbonate ions. The bile acid diffuses through cholangiocytes and returns to sinusoids via periductal capillary channels and is secreted into bile. UDCA: Ursodeoxycholic acid; CA: Carbonic anhydrase.