TABLE 3

Values of EC50 and Emax (± S.E.) for induction of CYP3A4 mRNA and midazolam-1′-hydroxylase activity by rifampin

The S.E. values are determined by the variability in the fit parameters obtained for each independent run; n = number of independent runs.

Rifampinn
DonorCYP3A4 mRNAaCYP3A4 Activitya
EC50Emax ± S.E.EC50Emax ± S.E.
Geometric MeanRangebGeometric MeanRange
μMμMμMμM
HH10890.600.53–0.6845.2 ± 16.70.570.30–1.096.1 ± 0.92
HC7-41.00.82–1.2253.6 ± 10.40.570.28–1.1311.1 ± 1.84
FOS1.160.54–2.4737.1 ± 10.20.360.22–0.605.0 ± 1.23
  • a Fold induction in CYP3A4 mRNA or enzyme activity (midazolam hydroxylation) expressed as pmol/min/106 cells.

  • b The EC50 range for rifampin reflects ±1 geometric S.E.