Testosterone inhibits matrix metalloproteinase-1 production in human endometrial stromal cells in vitro

The synergistic effects of testosterone and phophodiesterase-5 inhibitor combination on oxidative stress markers, matrix metalloproteinases and oxidative DNA damage: A randomized controlled experimental study

PURPOSE

To investigate the effects of combined tadalafil and testosterone usage on oxidative stress, DNA damage and MMPs in testosterone deficiency.

METHODS

Fifty rats were randomly divided into 5 groups (group-1: sham group-placebo, group-2: bilateral orchiectomy (ORX), group-3: bilateral ORX+tadalafil, group-4: bilateral ORX+testosterone, group-5: bilateral ORX+tadalafil+testosterone). Group-3 received tadalafil (5mg/kg/day, oral). Group-4 was administered testosterone undecanoate (100mg/kg i.m., single dose). Group-5 was administered a combination of tadalafil and testosterone undecanoate. All groups were compared with regard to serum nicotinamide adenine dinucleotide phosphate oxidase-4 (NOX-4), total thiol, matrix metalloproteinase-2 (MMP-2), MMP-3 and MMP-9, tissue inhibitor of metalloproteinases-1 (TIMP-1) and TIMP-2 and 8-hydroxy-2-deoxy guanosine (8-OHdG) levels.

RESULTS

Total thiol levels of group-2 were significantly lower than the other groups and thiol levels were higher in group-1 and group-5 than in the other groups. NOX4, MMP2 and 9 levels in group-2 were higher than in the other groups. MMP-9 levels in group-5 were lower than in groups 3 and 4 (p=.001). The level of 8-OHdG in groups 2 and 3 was higher than in the other groups (p=.001). In correlation analysis, 8-OHdG, MMP2, and 9 levels were negatively correlated with total thiol, whereas NOX4 and 8-OHdG levels were positively correlated with MMPs values.

CONCLUSIONS

The combination of testosterone with PDE-5 inhibitor suppresses MMP-9 levels and increases total thiol levels better than testosterone alone and tadalafil alone. Therefore, testosterone can be considered for use with PDE-5 inhibitor from the initial stage in case of testosterone deficiency.

Metformin reduces androgen receptor and upregulates homeobox A10 expression in uterine endometrium in women with polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) causes anovulation and is associated with a reduced clinical pregnancy rate. Metformin, which is widely used for treating PCOS, can lead to successful pregnancy by restoring the ovulation cycle and possibly improving endometrial abnormality during the implantation period. However, the mechanism by which metformin improves endometrial abnormality remains unknown. Women with PCOS have an aberrant expression of steroid hormone receptors and homeobox A10 (HOXA10), which is essential for embryo implantation in the endometrium.

METHODS

In this study, we examined whether metformin affects androgen receptor (AR) and HOXA10 expression in PCOS endometrium in vivo and in human endometrial cell lines in vitro. Expression of AR and HOXA10 was evaluated by immunohistochemistry, fluorescent immunocytochemistry, and western blot analysis.

RESULTS

AR expression was localized in both epithelial and stromal cells; however, HOXA10 expression was limited to only stromal cells in this study. In women with PCOS, 3 months after metformin treatment, the expression of AR was reduced in epithelial and stromal cells in comparison to their levels before treatment. In contrast, HOXA10 expression in the stromal cells with metformin treatment increased in comparison to its level before treatment. Further, we showed that metformin counteracted the testosterone-induced AR expression in both Ishikawa cells and human endometrial stromal cells (HESCs); whereas, metformin partly restored the testosterone-reduced HOXA10 expression in HESCs in vitro.

CONCLUSIONS

Our results suggest that metformin may have a direct effect on the abnormal endometrial environment of androgen excess in women with PCOS.

TRIAL REGISTRATION

The study was approved by the Ethical Committee of Fukushima Medical University (approval no. 504, approval date. July 6, 2006), and written informed consent was obtained from all patients. https://www.fmu.ac.jp/univ/sangaku/rinri.html.

Uncovering the pharmacological mechanism of motherwort (Leonurus japonicus Houtt.) for treating menstrual disorders: A systems pharmacology approach

Leonurus japonicus (motherwort) is a traditional Chinese medicine that is widely used to treat menstrual disorders (MDs). However, the pharmacological mechanisms that underlie its clinical application remain unclear. In this study, a network pharmacology-based approach was used that integrated drug-likeness evaluation, oral bioavailability prediction, target exploration, network construction, bioinformatic annotation and molecular docking to investigate the mechanisms that underlie motherwort treatment for MDs. In total, 29 bioactive compounds were collected from 51 compounds in motherwort, which shared 17 common MDs-related targets. Network analysis indicated that motherwort played a therapeutic role in MDs treatment through multiple components that acted on multiple targets. Pathway enrichment analysis showed that the putative targets of motherwort were primarily involved in various pathways associated with the endocrine system, cancers, vascular system, and anti-inflammation process. Notably, five targets (i.e., AKT1, PTGS2, ESR1, AR and PPARG) were screened as hub genes based on a degree algorithm. Moreover, most of the bioactive components in motherwort had good binding ability with these genes, implying that motherwort could regulate their biological function. Collectively, this study elucidated the molecular mechanisms that underlay the efficiency of motherwort against MDs and demonstrated the potential of network pharmacology as an approach to uncover the action mechanism of herbal medicines.

Thyroid Hormone Facilitates in vitro Decidualization of Human Endometrial Stromal Cells via Thyroid Hormone Receptors

Endometrial stromal cells differentiate into decidual cells through the process of decidualization. This differentiation is critical for embryo implantation and the successful establishment of pregnancy. Recent epidemiological studies have suggested that thyroid hormone is important in the endometrium during implantation, and it is commonly believed that thyroid hormone is essential for proper development, differentiation, growth, and metabolism. This study aimed to investigate the impact of thyroid hormone on decidualization in human endometrial stromal cells (hESCs) and define its physiological roles in vitro by gene targeting. To identify the expression patterns of thyroid hormone, we performed gene expression profiling of hESCs during decidualization after treating them with the thyroid hormone levothyroxine (LT4). A major increase in decidual response was observed after combined treatment with ovarian steroid hormones and thyroid hormone. Moreover, LT4 treatment also affected the regulation of many transcription factors important for decidualization. We found that type 3 deiodinase, which is particularly important in fetal and placental tissues, was upregulated during decidualization in the presence of thyroid hormone. Further, it was observed that progesterone receptor, an ovarian steroid hormone receptor, was involved in thyroid hormone-induced decidualization. In the absence of thyroid hormone receptor (TR), due to the simultaneous silencing of TRα and TRβ, thyroid hormone expression was unchanged during decidualization. In summary, we demonstrated that thyroid hormone is essential for decidualization in the endometrium. This is the first in vitro study to find impaired decidualization as a possible cause of infertility in subclinical hypothyroidism (SCH) patients.

How do elevated levels of testosterone affect the function of the human fallopian tube and fertility?-New insights

Excess testosterone levels affect up to 20% of the female population worldwide and are a key component in the pathogenesis of polycystic ovary syndrome. However, little is known about how excess testosterone affects the function of the human fallopian tube-the site of gamete transport, fertilization, and early embryogenesis. Therefore, this study aimed to characterize alterations caused by long-term exposure to male testosterone levels. For this purpose, the Fallopian tubes of nine female-to-male transsexuals, who had been undergoing testosterone treatment for 1-3 years, were compared with the tubes of 19 cycling patients. In the ampulla, testosterone treatment resulted in extensive luminal accumulations of secretions and cell debris which caused ciliary clumping and luminal blockage. Additionally, the percentage of ciliated cells in the ampulla was significantly increased. Transsexual patients, who had had sexual intercourse before surgery, showed spermatozoa trapped in mucus. Finally, in the isthmus complete luminal collapse occurred. Our results imply that fertility in women with elevated levels of testosterone is altered by tubal luminal obstruction resulting in impaired gamete transport and survival.

Gender in cardiac resynchronisation therapy

Introduction: Gender differences in cardiac resynchronisation therapy (CRT) response are not clear enough. This study aimed to assess gender influence on systemic inflammation, neurohormonal activation, fibrosis in patients with congestive heart failure (CHF) and CRT.

Methods: We compared group I (61 men) and group II (16 women) of patients undergoing CRT. Plasma levels of Nt-proBNP, interleukin (IL)-1β, IL-6, IL-10, tumor necrosis factor alpha (TNF-α), C-reactive protein, galectin-3 (Gal-3), metalloproteinase-9 (MMP-9), tissue inhibitors of metalloproteinase 1 and 4 (TIMP-1, TIMP-4), ratio MMP-9/TIMP-1, MMP-9/TIMP-4 were measured. According to dynamics of left ventricular end-systolic volume patients were classified into non-responders, responders, super-responders.

Results: Women more likely had left bundle branch block (81.3 vs 47.5%, P = 0.016), were more super-responders (66.7 vs 30.5%). Both groups showed decrease of IL-6 (P < 0.05), TNF-α (P < 0.001; P < 0.05), NT-proBNP (P = 0.001; P < 0.05), Gal-3 (P < 0.05). In women there was decrease of IL-6 by 44.4 vs 23.5% in men (PP = 0.029), TNF-α by 41.4 vs 30.9%, NT-proBNP by 73.3 vs 46% (P = 0.002), Gal-3 by 82.3 vs 64.9% (P < 0.05). Group I also showed decrease of IL-10 by 34.2% (P < 0.05). Group dynamics of TIMP-1 was opposite: men showed tendency to reduction of TIMP-1 (P = 0.054), women showed increase of TIMP-1 (P < 0.05). Besides, men showed decrease of MMP-9 (P < 0.05) and ratio MMP-9/TIMP-4 (P < 0.05).

Conclusion: The best response to CRT is associated with female gender explained by greater decrease of neurohormonal activation, systemic inflammation and fibrosis. The revealed opposite dynamics of TIMP-1 in the groups can demonstrate the existence of gender features of matrix metalloproteinase system activity and their tissue inhibitors.

Requirement of heart and neural crest derivatives-expressed transcript 2 during decidualization of human endometrial stromal cells in vitro

OBJECTIVE

To investigate the role of heart and neural crest derivatives-expressed transcript 2 (HAND2) during decidualization of human endometrial stromal cells (ESCs).

DESIGN

In vitro experiment.

SETTING

Research laboratory.

PATIENT(S)

Twenty-six patients undergoing hysterectomy for benign reasons.

INTERVENTION(S)

ESCs were cultured for 12 days with HAND2 small interfering RNA (siRNA) or nonsilencing RNA during decidualization by medroxyprogesterone acetate (MPA) and E2.

MAIN OUTCOME MEASURE(S)

Decidualization was monitored by changes in cellular morphology and the expression of several decidual-specific genes.

RESULT(S)

HAND2 siRNA effectively suppressed HAND2 levels in ESCs after 12 days of E2 + MPA treatment. ESCs cultured with HAND2 siRNA retained a long fibroblast-like shape, whereas the cells cultured with control siRNA transformed into enlarged polygonal cells. Silencing of HAND2 expression significantly reduced connexin-43 involved in the morphologic changes. HAND2 silencing significantly reduced the mRNA levels of fibulin-1, prolactin, tissue inhibitor of metalloproteinase 3, interleukin-15, and forkhead box O1A (FOXO1A), but had no effect on the mRNA levels of dickkopf-1, serum glucocorticoid kinase 1, and insulin-like growth factor-binding protein 5. HAND2 siRNA effectively suppressed the levels of nuclear FOXO1A protein as a regulator of decidualization.

CONCLUSION(S)

These results suggest that HAND2 plays a key role in the regulation of progestin-induced decidualization of human ESCs.

Testosterone reduces knee passive range of motion and expression of relaxin receptor isoforms via 5α-dihydrotestosterone and androgen receptor binding

Ovarian steroids such as estrogen and progesterone have been reported to influence knee laxity. The effect of testosterone, however, remains unknown. This study investigated the effect of testosterone on the knee range of motion (ROM) and the molecular mechanisms that might involve changes in the expression of relaxin receptor isoforms, Rxfp1 and Rxfp2 in the patella tendon and lateral collateral ligament of the female rat knee. Ovariectomized adult female Wistar rats received three days treatment with peanut oil (control), testosterone (125 and 250 μg/kg) and testosterone (125 and 250 μg/kg) plus flutamide, an androgen receptor blocker or finasteride, a 5α-reductase inhibitor. Duplicate groups received similar treatment however in the presence of relaxin (25 ng/kg). A day after the last drug injection, knee passive ROM was measured by using a digital miniature goniometer. Both tendon and ligament were harvested and then analysed for protein and mRNA expression for Rxfp1 and Rxfp2 respectively. Knee passive ROM, Rxfp1 and Rxfp2 expression were significantly reduced following treatment with testosterone. Flutamide or finasteride administration antagonized the testosterone effect. Concomitant administration of testosterone and relaxin did not result in a significant change in knee ROM as compared to testosterone only treatment; however this was significantly increased following flutamide or finasteride addition. Testosterone effect on knee passive ROM is likely mediated via dihydro-testosterone (DHT), and involves downregulation of Rxfp1 and Rxfp2 expression, which may provide the mechanism underlying testosterone-induced decrease in female knee laxity.

Progestin-induced heart and neural crest derivatives expressed transcript 2 is associated with fibulin-1 expression in human endometrial stromal cells

OBJECTIVE

To investigate whether heart and neural crest derivatives expressed transcript 2 (HAND2) regulates fibulin-1 (FBLN1) expression during decidualization of human endometrial stromal cells (ESCs).

DESIGN

In vitro experiment.

SETTING

Research laboratory.

PATIENT(S)

Twenty-four patients undergoing hysterectomy for benign reasons.

INTERVENTION(S)

ESCs were cultured with various progestins (medroxyprogesterone acetate [MPA], norethisterone, levonorgestrel, dienogest, and P), E(2), dexamethasone, and/or 8-bromoadenosine 3', 5'-cyclic monophosphate (8-Br-cAMP). HAND2 and FBLN1 were silenced by small interfering RNA technology.

MAIN OUTCOME MEASURE(S)

HAND2 and FBLN1 expression levels were assessed by real-time polymerase chain reaction and Western blot analysis.

RESULT(S)

MPA or E(2) + MPA increased HAND2 mRNA levels in ESCs in a time- and dose-dependent manner, and this stimulatory effect was blocked by RU-486 (P receptor antagonist). HAND2 was increased by E(2) + MPA earlier than FBLN1. Simultaneous MPA and 8-Br-cAMP treatment synergistically enhanced HAND2 mRNA levels. P and all the progestins significantly increased HAND2 mRNA levels, whereas E(2), 8-Br-cAMP, or dexamethasone alone had no effect. Silencing of HAND2 expression significantly reduced FBLN1 expression, whereas FBLN1 silencing had no effect on HAND2 expression.

CONCLUSION(S)

These results suggest that progestin-induced HAND2 contributes to FBLN1 expression in human ESCs.

The endocrine and paracrine control of menstruation

During the reproductive life, the human endometrium undergoes cycles of substantial remodeling including, at menstruation, a massive but delimited tissue breakdown immediately followed by scarless repair. The present review aims at summarizing the current knowledge on the endocrine and paracrine control of menstruation in the light of recent observations that undermine obsolete dogmas. Menstruation can be globally considered as a response to falling progesterone concentration. However, tissue breakdown is heterogeneous and tightly controlled in space and time by a complex network of regulators and effectors, including cytokines, chemokines, proteases and various components of an inflammatory response. Moreover, menstruation must be regarded as part of a complex and integrated mechanism of tissue remodeling including features that precede and follow tissue lysis, i.e. decidualization and immediate post-menstrual regeneration. The understanding of the regulation of menstruation is of major basic and clinical interest. Indeed, these mechanisms largely overlap with those controlling other histopathological occurrences of tissue remodeling, such as development and cancer, and inappropriate control of menstrual features is a major potential cause of two frequent endometrial pathologies (i.e. abnormal uterine bleeding and endometriosis).

Pelvic floor disorders: linking genetic risk factors to biochemical changes

Pelvic floor disorders (PFDs) such as stress urinary incontinence (SUI) and pelvic organ prolapse (POP) may share a common pathophysiological process related to pelvic floor tissue laxity and loss of support. We reviewed recent literature on observed biochemical changes in women with SUI and POP, linking them to genetic predisposition. We found that studies of pelvic tissues showed differences between control subjects and women with POP and SUI in collagen and elastin structure at a molecular and fibrillar level. Studies were heterogeneous but showed a trend towards decreased collagen and elastin content. The contribution of matrix metalloproteinases to increased collagenolysis can be related to genetic polymorphisms present in higher frequency in women with PFD. Extracellular matrix (ECM) protein turnover plays a role in the development of POP and SUI, but much remains to be understood of this complex dynamic interplay of enzymes, proteins and molecules. Genotyping of candidate genes participating in ECM formation will elucidate the missing link between the manifestation of the disease and the biochemical changes observed systematically, in addition to those in the pelvic floor.

Progestins inhibit estradiol-induced vascular endothelial growth factor and stromal cell-derived factor 1 in human endometrial stromal cells

OBJECTIVE

To investigate whether 17β-estradiol (E(2)) and progestins exert direct effects on vascular endothelial growth factor (VEGF) and stromal cell-derived factor 1 (SDF-1/CXCL12) in human endometrial stromal cells (ESCs) and thereby to clarify the regulatory function of these local angiogenic factors in the endometrium.

DESIGN

In vitro experiment.

SETTING

Research laboratory at Kansai Medical University.

PATIENT(S)

Fourteen patients undergoing hysterectomy for benign reasons.

INTERVENTION(S)

ESCs were cultured with E(2) and/or various clinically relevant progestins (medroxyprogesterone acetate [MPA], norethisterone [NET], levonorgestrel [LNG], dienogest [DNG], and progesterone [P]).

MAIN OUTCOME MEASURE(S)

The mRNA levels and production of VEGF and SDF-1 were assessed by real-time reverse-transcription polymerase chain reaction and ELISA, respectively.

RESULT(S)

E(2) significantly induced the mRNA levels and protein production of VEGF and SDF-1 in ESCs. MPA could antagonize the E(2)-stimulated effects in a time- and dose-dependent manner, and this effect could be reversed by RU-486 (P receptor antagonist). All of the progestins (MPA, NET, LNG, and DNG; 10(-9) to 10(-7) mol/L) attenuated E(2)-induced VEGF and SDF-1 production, whereas P showed these inhibitory effects only when present in a high concentration (10(-7) mol/L).

CONCLUSION(S)

Progestins have inhibitory effects on E(2)-induced VEGF and SDF-1 in ESCs. These results may indicate a potential mechanism for action of the female sex steroids in the human endometrium that can be helpful for various clinical applications.

NSSR1 is regulated by testosterone in the mouse uterus and extensively expressed in endometrial carcinoma

Neural salient serine/arginine-rich protein 1 (NSSR1) has been found to play important roles in inhibiting alternative splicing during heat shock and mitosis and is predominantly expressed in neural tissues such as cerebral neurons, cerebellar Purkinje cells and bipolar cells of the retina. Recently, NSSR1 has also been shown to be highly expressed in the testes, suggesting its potential roles in reproductive system. In this report, the expression of NSSR1 in the columnar epithelium of the endometrium and gland epithelium during the development of the mouse uterus, the regulation of NSSR1 level by testosterone in the adult mouse uterus, and expression level of NSSR1 in both human endometrial carcinomas and ovarian cancers were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR), Western blot, and immunohistochemistry. We demonstrated that the expression of NSSR1 was developmentally regulated in the columnar epithelium of the endometrium and gland epithelium in the mouse uterus. Additionally, the NSSR1 level in the mouse uterus was maintained and regulated by testosterone. Interestingly, an enhanced level of NSSR1 was observed in both human endometrial carcinomas and ovarian cancers. Our results suggest that expression and distribution of NSSR1 is developmentally and hormonally regulated and up-regulated in endometrial carcinomas as well as ovarian cancers, indicating its potential involvement in uterine development and tumorgenesis.

Prostaglandin treatment is associated with a withdrawal of progesterone and androgen at the receptor level in the uterine cervix

Treatment with prostaglandin(PG)-E2 is clinically efficient for cervical priming. The aim of this study was to evaluate the impact of PG-E2 on the expression of the progesterone (PR), androgen (AR) and glucocorticoid (GR) receptors in human uterine cervix in prolonged pregnancy. The study groups were postterm nulliparous women with unripe cervices undergoing cervical priming with PG-E2 before labor induction. Responders (n = 12) who delivered vaginally were compared with non-responders (n = 10), who underwent cesarean section due to failure to progress to the active phase of labor. Controls (n = 18) with vaginal partus at a normal gestational age served as a reference group. Cervical levels of PR-A and PR- B isoforms, AR and GR, serum levels of their ligands and sex hormone-binding globulin (SHBG) were quantified. The responder group displayed lower total PR-AB and AR protein levels as compared to non-responders, and lower PR-B and AR protein levels as compared to controls. In addition, the PR mRNA level was lower in responders as compared to non-responders. The GR protein level did not differ between the groups. We conclude that successful PG-E2 priming was followed by a progesterone and androgen withdrawal at the receptor level in the uterine cervix.

Estrogen and selective estrogen receptor modulators regulate vascular endothelial growth factor and soluble vascular endothelial growth factor receptor 1 in human endometrial stromal cells

OBJECTIVE

To determine whether 17beta-estradiol (E(2)) and selective estrogen receptor modulators can regulate vascular endothelial growth factor (VEGF) and soluble VEGF receptor 1 (sVEGFR-1) as a VEGF antagonist in human endometrial stromal cells (ESCs).

DESIGN

In vitro experiment.

SETTING

Research laboratory at Kansai Medical University.

PATIENT(S)

Sixteen patients undergoing hysterectomy for benign reasons.

INTERVENTION(S)

The ESCs were cultured with E(2), 4-hydroxytamoxifen (OHT), and raloxifene.

MAIN OUTCOME MEASURE(S)

The VEGF and sVEGFR-1 messenger RNA (mRNA) levels in ESCs were determined using quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Free (unbound) VEGF and sVEGFR-1 protein levels from ESCs were measured using ELISA kits.

RESULT(S)

The E(2) significantly induced VEGF mRNA levels, whereas E2 caused a significant decrease in sVEGFR-1 messenger RNA (mRNA) levels. The E(2) or OHT significantly increased the VEGF production levels and attenuated the sVEGFR-1 production compared with control, but raloxifene had no significant effect. The decrease in levels of free VEGF was proportional to the increase in sVEGFR-1 levels in the culture media of ESCs.

CONCLUSION(S)

The E(2) or OHT stimulates VEGF production and concurrently attenuates sVEGFR-1 production in ESCs. This consequential increase in VEGF:sVEGFR-1 ratio might enhance the biological effects of VEGF on the angiogenic environment in human endometrium.

Subfertile female androgen receptor knockout mice exhibit defects in neuroendocrine signaling, intraovarian function, and uterine development but not uterine function

Female androgen receptor (AR) knockout mice (AR(-/-)) generated by an in-frame Ar exon 3 deletion are subfertile, but the mechanism is not clearly defined. To distinguish between extra- and intraovarian defects, reciprocal ovarian transplants were undertaken. Ovariectomized AR(-/-) hosts with wild-type (AR(+/+)) ovary transplants displayed abnormal estrus cycles, with longer cycles (50%, P < 0.05), and 66% were infertile (P < 0.05), whereas AR(+/+) hosts with either AR(-/-) or surgical control AR(+/+) ovary transplants displayed normal estrus cycles and fertility. These data imply a neuroendocrine defect, which is further supported by increased FSH (P <0.05) and estradiol (P <0.05), and greater LH suppressibility by estradiol in AR(-/-) females at estrus (P <0.05). Additional intraovarian defects were observed by the finding that both experimental transplant groups exhibited significantly reduced pups per litter (P < 0.05) and corpora lutea numbers (P < 0.05) compared with surgical controls. All groups exhibited normal uterine and lactation functions. AR(-/-) uteri were morphologically different from AR(+/+) with an increase in horn length (P < 0.01) but a reduction in uterine diameter (P < 0.05), total uterine area (P < 0.05), endometrial area (P < 0.05), and myometrial area (P < 0.01) at diestrus, indicating a role for AR in uterine growth and development. Both experimental transplant groups displayed a significant reduction in uterine diameter (P < 0.01) compared with transplanted wild-type controls, indicating a role for both AR-mediated intraovarian and intrauterine influences on uterine physiology. In conclusion, these data provide direct evidence that extraovarian neuroendocrine, but not uterine effects, as well as local intraovarian AR-mediated actions are important in maintaining female fertility, and a disruption of AR signaling leads to altered uterine development.

Testosterone replacement therapy in the climacteric: benefits beyond sexuality

Testosterone therapy during menopause has a wide range of benefits that reach beyond the realm of human sexuality. This is a consequence not only of the widespread distribution of androgen receptors in various extragonadal tissues but also of the conversion of androgens to estrogens in the tissues in which aromatase expression is present. For this reason, testosterone therapy during the climacteric years will not only supply androgens but will also stimulate estrogen production in tissues that express aromatase. Furthermore, the bioavailability of androgens to the tissues depends not only on the rate of their production by the postmenopausal ovaries and adrenals but also on the circulating levels of sex hormone-binding globulin (SHBG). Tibolone inhibits SHBG production in the liver, thus increasing free testosterone levels. The association of tibolone with testosterone as a form of androgen replacement therapy during the climacteric is discussed, as is the use of low-dose testosterone, tibolone or the association of both in perimenopausal patients with signs of androgen deficiency. Testosterone treatment has a boosting effect not only on human sexuality but also on the sensation of well-being, a stimulatory effect conferred by the increase in beta-endorphins.