Tibolone is not aromatized in postmenopausal women

@article{Kloosterboer2008TiboloneIN,
  title={Tibolone is not aromatized in postmenopausal women},
  author={H. Kloosterboer},
  journal={Climacteric},
  year={2008},
  volume={11},
  pages={175 - 176}
}
Tibolone is not aromatized in postmenopausal women In the article of Kuhl and Wiegratz entitled ‘Can 19-nortestosterone derivatives be aromatized in the liver of adult humans? Are there clinical implications?’, the authors made the statement that the producer of tibolone was withholding clinical data about the aromatization of tibolone to 7a-methyl-ethinylestradiol (7a-MEE). This is not correct, because the results of the study were submitted to Menopause in June 2006, accepted in September… Expand
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Topics from this paper

Recent advances on the action of estrogens and progestogens in normal and pathological human endometrium
TLDR
Treatment with hormone replacement therapy (estrogens+progestogens), as well as with tibolone, is most effective in protecting this tissue by climacteric alterations, owing to the significant decrease of ovarian hormones. Expand
Vascular resistance of central retinal and ophthalmic arteries in postmenopausal women after use of tibolone
TLDR
It is demonstrated that tibolone administration to healthy postmenopausal women does not affect the resistance of small-caliber cerebral arteries and is compared with placebo using transorbital ultrasound with Doppler velocimetry. Expand
[Tibolone's effect on retinal and ophthalmic arteries flowmetry].
  • M.A.M. Souza, S. Geber
  • Medicine
  • Revista brasileira de ginecologia e obstetricia : revista da Federacao Brasileira das Sociedades de Ginecologia e Obstetricia
  • 2008
TLDR
In both groups, the women's characteristics were similar in age, menopause duration, body mass index, arterial blood pressure, deliveries and cardiac rate, and the tibolone and control groups did not show any significant difference in regard to the above indexes in the end of the study. Expand

References

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Can 19-nortestosterone derivatives be aromatized in the liver of adult humans? Are there clinical implications?
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  • Medicine
  • Climacteric : the journal of the International Menopause Society
  • 2007
TLDR
19-nortestosterone derivatives (norethisterone, norethynodrel, tibolone) can readily be aromatized in the adult human liver, which leads to the formation of the potent estrogens ethinylestradiol from norehisterone or nore fourthodrel and 7α-methyl-ethinylest radiol from tibiaolone. Expand
Formation of 7&agr;-methyl-ethinyl estradiol during treatment with tibolone
TLDR
Investigation of whether tibolone, which is orally used for hormone replacement therapy, is transformed to a derivative of ethinyl estradiol (EE), demonstrates that, during daily treatment of women with 2.5 mg tiblone, a small proportion of tIBolone is transformation to 7&agr;-methyl-EE. Expand
7&agr;-Methyl-ethinyl estradiol is not a metabolite of tibolone but a chemical stress artifact
TLDR
7&agr;-MEE is not a metabolite of tibolone but is a chemical artifact generated during analytical procedures with derivatization, and cannot be demonstrated in plasma from postmenopausal women after single or multiple doses of tIBolone. Expand
Aromatization of 7α-Methyl-19-nortestosterone by human placental microsomes in vitro
Abstract Part of the biological effects of testosterone (T) are mediated by its enzymatic reduction to 5α-dihydrotestosterone (DHT) or aromatization to estradiol (E 2 ). 7α-Methyl-19-nortestosteroneExpand
Endometrial effects of tibolone.
TLDR
The Tibolone Histology of the Endometrium and Breast Endpoints Study results confirm previous findings that tibolone does not induce endometrial hyperplasia or carcinoma in postmenopausal women, and it is associated with a better vaginal bleeding profile than CEE/MPA. Expand
In vivo conversion of norethisterone and norethisterone acetate to ethinyl etradiol in postmenopausal women.
TLDR
It is concluded that at therapeutic doses of the progestogens, the exposure to metabolically derived ethinyl estradiol is probably of little clinical significance not only in fertile women using oral contraceptive combination preparations containing norethisterone and ethinyl Estradiol, but also in postmenopausal women who receive oral doses of estradio for estrogen replacement. Expand
7a-Methyl-ethinyl estradiol is not a metabolite of tibolone but a chemical stress artefact
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  • 2007
Conversion of tibolone to 7a-methyl-ethinyl estradiol using gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry: interpretation and clinical implications
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