Nor-ursodeoxycholic acid in hepatobiliary diseases: A narrative review

Figure 3 The key differences between ursodeoxycholic acid and nor-ursodeoxycholic acid lie in the degree of cholehepatic shunt, biocarbonate secretion, choleresis, and farnesoid X receptor agonism. Nor-ursodeoxycholic acid demonstrates higher efficiency in bicarbonate secretion and choleresis in hepatocytes as compared to ursodeoxycholic acid (Table 1). Though nor-ursodeoxycholic acid lacks farnesoid X receptor agonistic property, its direct action on the transforming growth factor-β and small mother against decapentaplegic pathway is responsible for the antifibrotic property. UDCA: Ursodeoxycholic acid; BSEP: Bile salt exporter protein; TGF: Transforming growth factor; SMAD: Small mothers against decapentaplegic; FXR: Farnesoid X receptor; NTCP: Sodium (Na) taurocholate cotransporting polypeptide; SLC10A1: Solute carrier family 10 member A1.