A comparison of 4β-hydroxycholesterol: Cholesterol and 6β-hydroxycortisol: Cortisol as markers of CYP3A4 induction

摘要

Aim: To compare plasma 4β-hydroxycholesterol:cholesterol with urinary 6β-hydroxycortisol:cortisol as markers of cytochrome P4503A4 activity before and after treatment with rifampicin for 2 weeks. Method: 6β-hydroxycortisol and cortisol were determined by liquid chromatography tandem mass spectrometry and 4β-hydroxycholesterol was determined by gas chromatography-mass spectrometry in three groups of healthy volunteers. Results: Induction ratios for 6β-hydroxycortisol:cortisol were 1.8, 3.9 and 4.5 for 20mgday-1, 100mgday-1 or 500mgday-1 of rifampicin, respectively. The corresponding ratios for 4β-hydroxycholesterol:cholesterol were 1.5, 2.4 and 3.8. Conclusions: Plasma 4β-hydroxycholesterol:cholesterol gave similar induction ratios to urinary 6β-hydroxycortisol:cortisol.