title: Cytochrome P450 3A4 activity in premenopausal and postmenopausal women, based on 6-beta-hydroxycortisol:cortisol ratios.
abstract: OBJECTIVE
  To characterize cytochrome P450 (CYP) 3A4 activity in premenopausal and postmenopausal women by evaluating the urinary 6-beta-hydroxycortisol:cortisol ratio.
  
  
  METHODS
  Prospective study
  
  
  METHODS
  Thirteen premenopausal and 13 postmenopausal women who were healthy and not receiving drugs known to affect CYP3A4 activity
  
  
  METHODS
  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.
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Pharmacy Practice and Science, University of Maryland, Baltimore 21201-1082, USA.
authors.forename: A H
authors.initials: AH
authors.lastname: Burstein
authors.forename: W G
authors.initials: WG
authors.lastname: Reiss
authors.forename: E
authors.initials: E
authors.lastname: Kantor
authors.forename: G D
authors.initials: GD
authors.lastname: Anderson
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D015415:Biomarkers / Q000652:urine; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000031:analogs & derivatives* / Q000652:urine*; D008875:Middle Aged; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D017698:Postmenopause / Q000378:metabolism*; D017697:Premenopause / Q000378:metabolism*; D013997:Time Factors
chemical_list: D015415:Biomarkers; C001380:6 beta-hydroxycortisol; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; C104464:CYP3A protein, human; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; D006854:Hydrocortisone