Studies on CYP3A activity during the menstrual cycle as measured by urinary 6β‐hydroxycortisol/cortisol

Abstract

The 6β‐OH‐cortisol/cortisol ratio (6β‐OHC/C) in urine is an endogenous marker of drug‐metabolizing enzyme cytochrome P450 3A (CYP3A). The primary aim of this single center, prospective, non‐interventional cohort study, was to investigate the variability of 6β‐OHC/C during the menstrual cycle. In addition, possible associations between the CYP3A activity and sex hormones, gut microbiota metabolite trimethylamine‐N‐Oxide (TMAO) and microRNA‐27b, respectively, were investigated. Serum and urinary samples from healthy, regularly menstruating women followed for two menstrual cycles were analyzed. Twenty‐six complete menstrual cycles including follicular, ovulatory, and luteal phase were defined based on hormone analyses in serum. 6β‐OHC/C were analyzed in urine and sex hormones, TMAO and miRNA‐27b were analyzed in serum at the same time points. 6β‐OHC/C did not vary between the follicular, ovulatory, or luteal phases. There was a difference in the relative miRNA‐27b expression between the follicular and ovulatory phase ( p = .03). A significant association was found between 6β‐OHC/C and progesterone during the follicular ( p = .005) and ovulatory ( p = .01) phases ( n = 26 for each phase). In addition, a significant association was found between the ratio and TMAO during the ovulatory ( p = .02) and luteal ( p = .002) phases. 6β‐OHC/C and gut microbiota TMAO were significantly associated ( p = .003) when evaluating all values, for all phases ( n = 78). Interestingly, the finding of an association between 6β‐OHC/C in urine and levels of TMAO in serum suggest that gut microbiota may affect CYP3A activity.

Development of a Simultaneous Liquid Chromatography-Tandem Mass Spectrometry Analytical Method for Urinary Endogenous Substrates and Metabolites for Predicting Cytochrome P450 3A4 Activity

“…To date, several biomarkers of CYP3A4 activity have been identified in plasma and urine; however, the most suitable CYP3A4 biomarkers for evaluating its activity have not been conclusively identified. [19][20][21][22][23][24][25][26][27][28] Therefore, a clinically available high-throughput method is required to investigate the utility of CYP3A4 biomarkers.…”

“…[43][44][45][46] In contrast, the 6β-OHC/C and 1β-OHDCA/DCA ratios in urine have been used as endogenous biomarkers for predicting CYP3A4 activity in previous studies that have adapted negative-ion detection modes for DCA and 1β-OHDCA. 19,[21][22][23][24][25][26]43) C and 6β-OHC can be detected in both the positive-and negative-ion modes, although 6β-OHC requires derivatization owing to the low sensitivity of LC-MS/MS and GC/MS. 26,27,43) Therefore, studies on 6β-OHC detection have primarily focused on the establishment of a validated method.…”

“…In previous studies, the concentration ratios of plasma 6β-OHC/C and urine 1β-OHDCA/DCA have been claimed to represent endogenous CYP3A4 biomarkers. 19,[21][22][23][24][25][26][27][28] In the present study, we evaluated the correlation between 6β-OHC/C and 1β-OHDCA/DCA concentration ratios in the urine. However, no strong correlation was observed between each ratio due to various possible factors, in addition to the sample size limitation.…”

“…To date, the concentration ratios of 4β-hydroxycholesterol to cholesterol, 6β-hydroxycortisol (6β-OHC) to cortisol (C), and 1β-hydroxydeoxycholic acid (1β-OHDCA) to deoxycholic acid (DCA) in the plasma or urine have been correlated with the concentration of drugs metabolized by CYP3A4. [19][20][21][22][23][24][25][26][27][28] Notably, 1β-OHDCA has been reported as a CYP3A4-specific biomarker, although CYP3A4 and CYP3A5 often exhibit an overlap in substrate specificity. 22) As 4β-hydroxycholesterol has a relatively long half-life (approximately 17 d) compared with that of other biomarkers, 29) 6β-OHC and 1β-OHDCA may represent better indicators of the actual CYP3A4 activity at the time of sample collection.…”