Induction of 
Hepatic Xanthine Oxidase by Taurocholate in Cholestatic Rats

Keimyung Medical Journal 2001;20(2):172-180.

Induction of Hepatic Xanthine Oxidase by Taurocholate in Cholestatic Rats

담즙울체 쥐에서 Taurocholate 부하에 의한 간의 Xanthine Oxidase 유도

정상호; 문교철

Abstract

Possible mechanisms of increase of xanthine oxidase (XO) activity in cholestatic rat liver and serum were studied. These hepatic and serum enzyme activities were determined in experimental rats with choledocho-caval shunt (CCS) or bile duct obstruction (BDO). The Michaelis-Menten constant of this hepatic enzyme were also measured. The activities of hepatic and serum XO as well as the Vmax value of this hepatic enzyme were found to be significantly increased in both CCS plus taurocholic acid (TCA) injected group; and BDO plus TCA injected group than in the control groups such as CCS alone and BDO alone. In addition; these serum and hepatic XO activities did not change in both the CCS plus tauroursodeoxycholic acid (TUDCA) injected group and the BDO plus TUDCA injected group. On the other hand; the Km value of the above hepatic enzyme did not change in any experimental group. Above results suggest that TCA induces biosynthesis of XO in the liver. The elevated activity of serum XO is most likely caused by increased hepatocytes membrane permeability due to TCA mediated liver cell necrosis.

Key Words: Bile duct obstuction, Choledocho-caval shunt, Taurocholic acid, Tauroursodeoxycholic acid, Xanthine oxidase