Correlation analyses reveals that UGT1A1 is responsible for Raloxifene 6-glucuronide but not Raloxifene 4'-glucuronide in liver. Treatment of expressed UGTs with alamethicin results in minor increases in enzyme activity, whereas in human intestinal microsomes, maximal increases of 8-fold for the Raloxifene 6-glucuronide are observed. Intrinsic clearance values in intestinal microsomes are 17 μl/min/mg for the Raloxifene 6-glucuronide[2].