Estrogen and progestin combination in hormone replacement therapy (HRT) increases the incidence of breast cancer, but decreases the endometrial cancer risk of unopposed estrogen. Therefore, a SERM such as Tibolone, that delivers the beneficial, but not the adverse side effects, of steroid hormones would be clinically advantageous. However, data from the Million Women Study suggests that Tibolone increases the risk of both breast and endometrial cancer. Herein, we assessed the estrogenic and progestagenic actions of Tibolone using transvaginal sonography studies and an in vitro model of breast (ZR-75, MCF7) and endometrial cancer (Ishikawa). The known cancer associated proteins (ER, EGFR, STATS, tissue factor and Bcl-xL) were selected for study. Transvaginal sonography demonstrated that postmenopausal women treated with Tibolone displayed a thinner endometrium than in the late proliferative phase, but had a phenotype characteristic of the secretory phase, thus demonstrating the estrogenic and progestagenic actions of this SERM. In vitro, Tibolone acted as an estrogen in downregulating ER and upregulating Bcl-xL, yet as progesterone, increasing STAT5 and tissue factor in breast cancer cells. The increase in tissue factor by Tibolone correlated with its coagulative potential. Interestingly, EGFR was up-regulated by progesterone in the breast and by estrogen in endometrial cells, while Tibolone increased protein levels in both cell types. In conclusion, this study further demonstrates the estrogenic and progestagenic nature of Tibolone. The pattern of regulation of known oncogenes in cells of breast and endometrial origin dictates caution and vigilance in the prescription of Tibolone and subsequent patient monitoring.
Tibolone estrogenic action, SERM menopausal therapy, hormone replacement therapy cancer, Tibolone breast cancer risk, progestagenic activity Tibolone, endometrial effects Tibolone, Million Women Study, synthetic steroid menopause, tissue-specific hormone action, menopausal symptom treatment
PMID 16238103 16238103 DOI 10.4067/s0716-97602005000200014 10.4067/s0716-97602005000200014
Cite this article
Sadarangani, A., Salgado, A. M., Kato, S., Pinto, M., Carvajal, A., Monso, C., Owen, G. I., & Vigil, P. (2005). In vivo and in vitro estrogenic and progestagenic actions of Tibolone. Biological research, 38(2-3), 245-258. https://doi.org/10.4067/s0716-97602005000200014
Sadarangani A, Salgado AM, Kato S, Pinto M, Carvajal A, Monso C, et al. In vivo and in vitro estrogenic and progestagenic actions of Tibolone. Biol Res. 2005;38(2-3):245-258. doi:10.4067/s0716-97602005000200014
Sadarangani, A., et al. "In vivo and in vitro estrogenic and progestagenic actions of Tibolone." Biological research, vol. 38, no. 2-3, 2005, pp. 245-258.
We agree with Lega and colleagues[1][1] that menopausal hormone therapy (MHT) has been shown in randomized controlled trials (RCTs) to be effective and safe for treating problematic vasomotor symptoms related to menopause. We also agree that treating menopausal vasomotor symptoms is important to
Perimenopause/MenopauseReproductive Endocrinology
Open Access
This study tested progesterone for perimenopausal hot flush ± night sweat (vasomotor symptom, VMS) treatment. It was a double-blind, randomized trial of 300 mg oral micronized progesterone@bedtime versus placebo for 3-months (m) after a 1-m untreated baseline during 2012/1-2017/4. We randomized untreated, non-depressed, screenand baseline-eligible by VMS, perimenopausal women (with flow within 1-year), ages 35-58 (n = 189). Participants aged 50 (± SD = 4.6) were mostly White, educated, minimally overweight with 63% in late perimenopause; 93% participated remotely. The 1° outcome was 3rd-m VMS Score difference. Participants recorded VMS number and intensity (0-4 scale)/24 h on a VMS Calendar. Randomization required VMS (intensity 2-4/4) of sufficient frequency and/or ≥ 2/week night sweat awakenings. Baseline total VMS Score (SD) was 12.2 (11.3) without assignment difference. Third-m VMS Score did not differ by therapy (Rate Difference - 1.51). However, the 95% CI [- 3.97, 0.95] P = 0.222, did not exclude 3, a minimal clinically important difference. Women perceived progesterone caused decreased night sweats (P = 0.023) and improved sleep quality (P = 0.005); it decreased perimenopause-related life interference (P = 0.017) without increased depression. No serious adverse events occurred. Perimenopausal night sweats ± hot flushes are variable; this RCT was underpowered but could not exclude a minimal clinically important VMS benefit. Perceived night sweats and sleep quality significantly improved.
Perimenopause/MenopauseReproductive Endocrinology
Open Access
Early menopause (<45 years) has significant impacts on bone, cardiovascular, and cognitive health. Several studies have suggested earlier menopause for women living with HIV; however, the current literature is limited by reliance on self-report data. We determined age at menopause in women living with HIV and socio-demographically similar HIV-negative women based on both self-report of menopause status (no menses for ≥12 months) and biochemical confirmation (defined as above plus follicle-stimulating hormone level ≥ 25 IU/mL). Multivariable median regression models assessed factors associated with menopause age, controlling for relevant confounders. Overall, 91 women living with HIV and 98 HIV-negative women were categorized as menopausal by self-report, compared to 83 and 92 by biochemical confirmation. Age at menopause did not differ significantly between groups, whether based on self-report (median [IQR]: 49.0 [45.3 to 53.0] vs. 50.0 [46.0 to 53.0] years; p = 0.28) or biochemical confirmation (50.0 [46.0 to 53.0] vs. 51.0 [46.0 to 53.0] years; p = 0.54). In the multivariable model, no HIV-related or psychosocial variables were associated with earlier age at menopause (all p > 0.05). Overall, HIV status per se was not statistically associated with an earlier age at menopause, emphasizing the importance of comparing socio-demographically similar women in reproductive health and HIV research.
Reproductive EndocrinologyPerimenopause/Menopause
Open Access
Obesity in women of reproductive age has a number of adverse metabolic effects, including Type II Diabetes (T2D), dyslipidemia, and cardiovascular disease. It is associated with increased menstrual irregularity, ovulatory dysfunction, development of insulin resistance and infertility. In women, estradiol is not only critical for reproductive function, but they also control food intake and energy expenditure. Food intake is known to change during the menstrual cycle in humans. This change in food intake is largely mediated by estradiol, which acts directly upon anorexigenic and orexigenic neurons, largely in the hypothalamus. Estradiol also acts indirectly with peripheral mediators such as glucagon like peptide-1 (GLP-1). Like estradiol, GLP-1 acts on receptors at the hypothalamus. This review describes the physiological and pathophysiological mechanisms governing the actions of estradiol during the menstrual cycle on food intake and energy expenditure and how estradiol acts with other weight-controlling molecules such as GLP-1. GLP-1 analogs have proven to be effective both to manage obesity and T2D in women. This review also highlights the relationship between steroid hormones and women's mental health. It explains how a decline or imbalance in estradiol levels affects insulin sensitivity in the brain. This can cause cerebral insulin resistance, which contributes to the development of conditions such as Parkinson's or Alzheimer's disease. The proper use of both estradiol and GLP-1 analogs can help to manage obesity and preserve an optimal mental health in women by reducing the mechanisms that trigger neurodegenerative disorders.