TABLE 3.

P450 inhibition of demethyl-IQ formation by liver microsomes from BNF-treated mice

Incubations were conducted for 30 min at 37°C with 0.06 mM IQ. Furafylline was preincubated for 10 min before addition of IQ. For those incubations, the control microsomal activity was 0.25 ± 0.01 nmol, which is not different from the control value above. Data are expressed as mean nanomole of demethyl-IQ ± S.E. with n = 3.

Test Agents	Type of P450 Inhibitor	Concentration	Activity	% of Total
		μM	nmol
Control			0.26 ± 0.04	100
Ellipticine	1A	10	0.03 ± 0.01*	12
		20	N.D.	0
Furafylline	1A2	20	0.22 ± 0.01	85
α-Naphthoflavone	1A	20	0.20 ± 0.01	77
		100	0.15 ± 0.02*	58
SKF-525A	Nonspecific	20	0.19 ± 0.04	73
		100	0.12 ± 0.02*	46
Ketoconazole	3A	20	0.17 ± 0.02*	65
		100	0.07 ± 0.04*	27
Sulfaphenazole	2C	20	0.19 ± 0.05	73
		100	0.20 ± 0.03	77

N.D., not detected.

^*p < 0.05 compared with control.