Enzymatic studies of glucuronide formation in impaired liver,4.

The liver glucuronyl transferase (GT) activity and uridine diphosphate glucuronic acid (UDPGA) content in the patients with viral hepatitis were determined using 4-methyl umbelliferone (4-MU) as a glucuronide receptor. The results were as follows: 1. In acute viral hepatitis, the decrease in the GT activity was more remarkable in the later stage of the recovery. In chronic viral hepatitis, the GT activity was decreased in accordance with the increase in the degree of liver injury. Liver UDPGA content was significantly reduced only in postnecrotic cirrhosis. 2. The decrease or injury in the parenchymal liver cells caused a decrease in the liver GT activity. These quantitative reductions in the liver parenchyme were not the only factor for the alteration in the GT activity of the liver. The results of the present study suggested an involvement of a qualitative change in the liver GT activity in human liver injuries, especially in the early stage of acute viral hepatitis; namely, there might be even an activation of the liver GT other than the reduction resulting from the decrease in the liver parenchyme. 3. The decrease in the liver GT activity correlated significantly with the decrease in the salicylamide glucuronide formation in vivo, while the alteration in the liver UDPGA content failed to correlate with that in the glucuronide formation in vivo. It was suggested that the velocity of in vivo UDPGA production rather than the UDPGA content of the liver was as important a rate-limiting factor for the glucuronide formation in vivo as the liver GT activity.