Effect of 4-methylumbelliferone on the oxidative metabolism of liver mitochondria in jaundiced rats and its relationship of choleretic action.

The effect of 4-methylumbelliferone (4-MU) on the oxidative metabolism of liver mitochondria and its relationship to choleretic action were investigated on 40 bile duct-ligated rats and 40 rats after biliary decompression. The oxidative metabolism of liver mitochondria fell rapidly to 50% of controls within 7 days after bile duct-ligation, whereas that in rats with 4-MU fell only slightly. Such effect of 4-MU on the liver mitochondrial metabolism was most prominent when it was administered to rats after biliary decompression. In rats with 4-MU the depressed oxidative metabolism of cholestatic liver mitochondria recovered rapidly toward normal with accelerated amelioration of serum total bilirubin as compared to that in rats without 4-MU after biliary decompression by loosening of the ligation of the common bile duct. Thus, 4-MU appeared to exert some stimulation or amelioration of the impaired liver mitochondrial metabolism due to jaundice, which may have a close relationship to its choleretic action or effective bile excretory action.