Table 3

Effects of chemical inhibitors on quinone-type metabolite 3 formation from troglitazone catalyzed by human liver microsomes (samples HL-3 and HL-4)

AdditionμMMetabolite 3 Formation
10 μM troglitazone30 μM troglitazone
HL-3HL-4HL-3HL-4
pmol/min/nmol P-450
None191  ± 18  (100)138  ± 18  (100)292  (100)200  (100)
Quercetin10204  ± 14  (107)80  ± 10  (58)387  (133)209  (97)
Sulfaphenazole10228  ± 16  (119)124  ± 9  (90)428  (147)200  (100)
Fluvoxamine10236  ± 21  (124)137  ± 11  (99)443  (152)212  (106)
Quinidine10211  ± 10  (110)141  ± 13  (102)319  (109)216  (108)
Ketoconazole1130  ± 11  (68)76  ± 6  (55)157  (54)100  (50)
Combination of
 quercetin and1092  ± 14∗∗  (48)44  ± 16∗∗  (32)n.d.n.d.
 ketoconazole1

Troglitazone (10 or 30 μM) was incubated with human liver microsomes (samples HL-3 and HL-4) in the absence or presence of chemical inhibitors. Data are means ± S.D. of triplicate (10 μM troglitazone) or means of duplicate (30 μM) determinations.

  • Values in parenthesis indicate percentage of control (none). n.d., not done.

  • p < .05, ∗∗p < .01.