Within-person variability of urinary 6β-hydroxycortisol to urinaryl ratios in Caucasian women

Zhi Chen, Lisa A. Dunning, Kristin E. Anderson, Jordan L. Holtzman, Wei Zheng

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Cortisol is metabolized to 6β-hydroxycortisol by human cytochrome P450-3A4 (CYP3A4), an important enzyme involved in the metabolism of a variety of exogenous and endogenous compounds. Both cortisol and 6β- hydroxycortisol are excreted in urine, and the ratio of these steroids has been proposed as an indicator of CYP3A4 activity. We evaluated within-person variability of this biomarker in 10 healthy Caucasian women, aged 23-58 years. Each study participant was asked to provide a fasting morning urine sample once a week consecutively for 8 weeks. Urinary cortisol and 6β-hydroxycortisol were determined by immunoassay kits purchased from the DiaSorin (Stillwater, MN) and the Stabiligen (Nancy, France), respectively. The coefficients of variation (CV) of urinary 6β-hydroxycortisol to cortisol ratios from study participants ranged from 16.7 to 51.4% (mean, 31.1%) over the study period. The level of the ratio measured in any single urine sample was correlated reasonably well with the average of the ratios over the 8-week study period from the same woman, with the mean correlation coefficient of 0.79. These results indicated that urinary 6β-hydroxycortisol to cortisol ratios measured in a spot urine sample may reflect the level of this biomarker over a relatively longer time period in Caucasian women, and thus, it can be used in epidemiologic studies as a biomarker to evaluate the association between CYP3A4 activity and disease risk.

Original languageEnglish (US)
Pages (from-to)67-70
Number of pages4
JournalSteroids
Volume69
Issue number1
DOIs
StatePublished - Jan 2004

Bibliographical note

Funding Information:
The authors thank Ms. Lois Murphy for assistance in data and specimen collection and volunteers for participating in the study. This work was supported by USPHS grant R03C70554.

Keywords

  • 6β-Hydroxycortisol to cortisol ratios
  • Biomarkers
  • CYP3A4
  • Epidemiology
  • Steroid

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