Effect of Scoparone on the Hepatic Microsomal UDPglucuronyltransferase Activity in Mice

The effect of scoparone on UDP glucuronyltransfearase in mouse hepatic microsomes was studied. After transment with scoparone, hepatic microsomal UDP glucuronyltransferase activity was increased with dose-dependent manner as compared to control. The V$_max$ value (control = 23.2 n moles/mg protein/min, scoparone = 31.2 n moles/ mg protein /min) without affecting the $K_m$ value (414 $\mu$M) for p-nitrophenol was increased by the scoparone treatment, and the pattern of kinetic studies for UDP-glucuronic acid was also similar to those of p-nitrophenol. Whereas, the hepatic microsomal UDP glucuronyl-transferase was not changed by the addition of scoparone in vitro. The results obtained suggest that the characteristics of increase in the enzyme activity may include induction of enzyme proteins.