Norursodeoxycholic acid (norUDCA) is a bile acid and the C23 homolog of UDCA .1,2 Unlike UDCA, norUDCA does not undergo conjugation to taurine or glycine and is secreted in an unchanged form, as trihydroxy derivatives, or as sulfate or glucuronide conjugates. Dietary administration of norUDCA (0.5% w/w) decreases serum levels of alanine aminotransferase (ALT) and alkaline phosphatase, markers of cholestasis, periductal fibrosis, and hepatic hydroxyproline content in an Mdr2-/- mouse model of sclerosing cholangitis.1
1.Fickert, P., Wagner, M., Marschall, H.-U., et al.24-norUrsodeoxycholic acid is superior to ursodeoxycholic acid in the treatment of sclerosing cholangitis in Mdr2 (Abcb4) knockout miceGastroenterology130(2)465-481(2006) 2.Hofmann, A.F., Zakko, S.F., Lira, M., et al.Novel biotransformation and physiological properties of norursodeoxycholic acid in humansHepatology42(6)1391-1398(2005)