Half-lives for mechanism-based inactivation and extent of competitive inhibition of EROD activity, in phenobarbital-induced guinea pig hepatic microsomes, by enantiomers of αMB
| Concentration | (−) αMB | (+) αMB | (±) αMB | |||
|---|---|---|---|---|---|---|
| t1/2 | EROD Activity2-a | t1/2 | EROD Activity2-a | t1/2 | EROD Activity2-a | |
| μM | min | % of control | min | % of control | min | % of control |
| 0.50 | 23.5 ± 6.4 | 96.5 ± 3.3 | 23.1 ± 2.3 | 99.5 ± 5.0 | 22.8 ± 6.0 | 95.5 ± 4.5 |
| 1.00 | 13.2 ± 1.8 | 95.2 ± 3.7 | 14.8 ± 0.6 | 94.7 ± 7.3 | 13.9 ± 1.7 | 92.7 ± 2.2 |
| 2.50 | 8.8 ± 0.7 | 91.9 ± 3.0 | 9.1 ± 0.5 | 88.9 ± 10.2 | 8.8 ± 0.7 | 87.3 ± 0.9 |
| 4.00 | 6.9 ± 0.8 | 88.5 ± 2.1 | 6.5 ± 1.0 | 87.2 ± 8.8 | 6.6 ± 0.9 | 82.9 ± 4.2 |
| 10.00 | 4.3 ± 0.4 | 80.5 ± 6.0 | 4.5 ± 0.5 | 85.3 ± 9.4 | 4.3 ± 0.2 | 77.4 ± 4.0 |
↵2-a The extent of competitive inhibition was determined by incubation of microsomes with inhibitor for 5 min at 37°C in the absence of NADPH. The control EROD activities (in the absence of inhibitor) for the experiments with (−) αMB, (+) αMB, and (±) αMB were 81.2 ± 12.7, 76.0 ± 6.9, and 74.0 ± 13.4 pmol/min/nmol of P450, respectively. All values are the mean ± SD of independent experiments performed in duplicate, using liver microsomes prepared from four individual animals (N = 4).