Figure 5.

Hepatic UGT1A protein expression and enzyme activity in diethylnitrosamine (DEN)‐treated htgUGT1A mice 40 wk after DEN‐induced hepatocarcinogenesis. A, Western blot analysis of hepatic UGT1A protein quantity in normal (N) and tumor (T) tissue. Increased protein levels were detected in DEN‐treated htgUGT1A–wild‐type (WT) mice, and a considerable upregulation was observed after DEN + coffee cotreatment especially in tumor tissue. B, UDP‐glucuronosyltransferase (UGT) enzyme activity against a proluciferin substrate shown as percent of substrate consumed. Catalytic UGT activity was significantly induced after coffee cotreatment in both mouse lines with higher protein activity measured in htgUGT1A‐WT mice. Each column represents the mean ± standard deviation. Groups without the same letter are significantly different; P < 0.05 was considered statistically significant