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Updated: Jul 18, 2026

Establishment of Rat Models Mimicking Gender-affirming Hormone Therapies
Published on: January 10, 2025
Dexamethasone as a probe for CYP3A4 metabolism: evidence of gender effect
F Puisset1, E Chatelut, A Sparreboom
1EA3035, Institut Claudius-Regaud, 31000 Toulouse, France.
Background:
A study was conducted to evaluate prospectively the correlation between docetaxel clearance and pharmacokinetics of dexamethasone previously obtained in 21 patients.
Patients And Methods:
Dexamethasone pharmacokinetics were performed in 17 patients 24 h before docetaxel treatment as monochemotherapy. Dexamethasone and docetaxel plasma concentrations were determined by HPLC methods. Determination of docetaxel unbound fraction in plasma was performed using microequilibrium dialysis.
Results:
Significant correlation was observed between observed plasma docetaxel clearances (CL(docetaxel)) and values predicted from dexamethasone plasma clearance (CL(dexa)), unbound plasma docetaxel fraction estimated from serum alpha1-acid glycoprotein level (fu(alpha1-AAG)), and hepatic metastasis status. However, after splitting of the prospective data set according to gender, no correlation was observed for males (R(2) = 0.08, NS, n = 10), then strong correlation was observed for females (R(2) = 0.78, P < 0.01, n = 7). Multivariate analysis was performed from data obtained in the women included in the first study and those of this prospective study (n = 18). Docetaxel CL was significantly correlated with CL(dexa) (P = 0.001) and fu(alpha1-AAG) (P = 0.01) according to the relationship (with +/-95% confidence intervals): CL(docetaxel) (l/h) = 1.92 (+/-0.94) x CL(dexa) (l/h) + 2.68 (+/-1.95) x fu(alpha1-AAG) (%) (R(2) = 0.68).
Conclusion:
Dexamethasone may be used to predict docetaxel clearances in females, but not in males.
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