Table 2

IC50 values for rosiglitazone, pioglitazone, and troglitazone against drug oxidation activities catalyzed by human hepatic microsomes

IsoformRosiglitazone IC50Pioglitazone IC50Troglitazone IC50
μM
CYP1A255.0NA23.4
CYP2A6NANA24.6
CYP2C89.589.382.33
CYP2C983.21002.73
CYP2C19NA83.325.7
CYP2D642.1NANA
CYP2E1NANANA
CYP3A428.012.314.5

Incubations were conducted with pooled human microsomes (n = 15) under conditions outlined underMaterials and Methods. The substrate probes were used at their in vitro Km values. A Micromass Quattro II or an LC tandem quadrupole mass spectrometer were used to monitor ions of the respective P450 marker metabolites

  • NA, no inhibition observed below 50%.