Cytochrome P450 3A4 activity in premenopausal and postmenopausal women, based on 6-beta-hydroxycortisol:cortisol ratios

Pharmacotherapy. Nov-Dec 1998;18(6):1271-6.


Study objective: To characterize cytochrome P450 (CYP) 3A4 activity in premenopausal and postmenopausal women by evaluating the urinary 6-beta-hydroxycortisol:cortisol ratio.

Design: Prospective study

Subjects: Thirteen premenopausal and 13 postmenopausal women who were healthy and not receiving drugs known to affect CYP3A4 activity

Interventions: Beginning on day 2 of menses, premenopausal women collected first morning urine samples every other day for a complete menstrual cycle. Postmenopausal women collected first morning urine every other day for 28 days.

Measurements and main results: Mean weekly 6-beta-hydroxycortisol:cortisol ratios did not differ during the phase (week) of the menstrual cycle. Daily ratios did not differ in postmenopausal women. No difference between premenopausal and postmenopausal women was found on comparing overall median ratios.

Conclusion: Cytochrome P450 3A4 activity as measured by 6-beta-hydroxy cortisol:cortisol ratio did not differ by week of menstrual cycle, suggesting no menstrual cycle-related changes. Menopause does not appear to be associated with differences in CYP3A4 activity, compared with premenopause.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Analysis of Variance
  • Biomarkers / urine
  • Cytochrome P-450 CYP3A
  • Cytochrome P-450 Enzyme System / metabolism*
  • Female
  • Humans
  • Hydrocortisone / analogs & derivatives*
  • Hydrocortisone / urine*
  • Middle Aged
  • Mixed Function Oxygenases / metabolism*
  • Postmenopause / metabolism*
  • Premenopause / metabolism*
  • Time Factors


  • Biomarkers
  • 6 beta-hydroxycortisol
  • Cytochrome P-450 Enzyme System
  • Mixed Function Oxygenases
  • CYP3A protein, human
  • Cytochrome P-450 CYP3A
  • CYP3A4 protein, human
  • Hydrocortisone