Effects of treatment with testosterone alone or in combination with estrogen on insulin sensitivity in postmenopausal women

Metabolic benefits afforded by estradiol and testosterone in both sexes: clinical considerations

Testosterone (T) and 17β-estradiol (E2) are produced in male and female humans and are potent metabolic regulators in both sexes. When E2 and T production stops or decreases during aging, metabolic dysfunction develops and promotes degenerative metabolic and vascular disease. Here, we discuss the shared benefits afforded by E2 and T for metabolic function human females and males. In females, E2 is central to bone and vascular health, subcutaneous adipose tissue distribution, skeletal muscle insulin sensitivity, antiinflammatory immune function, and mitochondrial health. However, T also plays a role in female skeletal, vascular, and metabolic health. In males, T's conversion to E2 is fundamental to bone and vascular health, as well as prevention of excess visceral adiposity and the promotion of insulin sensitivity via activation of the estrogen receptors. However, T and its metabolite dihydrotestosterone also prevent excess visceral adiposity and promote skeletal muscle growth and insulin sensitivity via activation of the androgen receptor. In conclusion, T and E2 are produced in both sexes at sex-specific concentrations and provide similar and potent metabolic benefits. Optimizing levels of both hormones may be beneficial to protect patients from cardiometabolic disease and frailty during aging, which requires further study.

Causal associations between insulin and Lp(a) levels in Caucasian population: a Mendelian randomization study

BACKGROUND

Numerous observational studies have demonstrated that circulating lipoprotein(a) [Lp(a)] might be inversely related to the risk of type 2 diabetes (T2D). However, recent Mendelian randomization (MR) studies do not consistently support this association. The results of in vitro research suggest that high insulin concentrations can suppress Lp(a) levels by affecting apolipoprotein(a) [apo(a)] synthesis. This study aimed to identify the relationship between genetically predicted insulin concentrations and Lp(a) levels, which may partly explain the associations between low Lp(a) levels and increased risk of T2D.

METHODS

Independent genetic variants strongly associated with fasting insulin levels were identified from meta-analyses of genome-wide association studies in European populations (GWASs) (N = 151,013). Summary level data for Lp(a) in the population of European ancestry were acquired from a GWAS in the UK Biobank (N = 361,194). The inverse-variance weighted (IVW) method approach was applied to perform two-sample summary-level MR. Robust methods for sensitivity analysis were utilized, such as MR‒Egger, the weighted median (WME) method, MR pleiotropy residual sum and outlier (MR-PRESSO), leave-one-out analysis, and MR Steiger.

RESULTS

Genetically predicted fasting insulin levels were negatively associated with Lp(a) levels (β = - 0.15, SE = 0.05, P = 0.003). The sensitivity analysis revealed that WME (β = - 0.26, SE = 0.07, P = 0.0002), but not MR‒Egger (β = - 0.22, SE = 0.13, P = 0.11), supported a causal relationship between genetically predisposed insulin levels and Lp(a).

CONCLUSION

Our MR study provides robust evidence supporting the association between genetically predicted increased insulin concentrations and decreased concentrations of Lp(a). These findings suggest that hyperinsulinaemia, which typically accompanies T2D, can partially explain the inverse relationship between low Lp(a) concentrations and an increased risk of T2D.

The Impact of Testosterone Therapy on Cardiovascular Risk Among Postmenopausal Women

Purpose

To summarize the current state of knowledge surrounding the impact of testosterone therapy on cardiovascular risk factors in postmenopausal women.

Methodology

In this scoping review, a comprehensive search of peer-reviewed literature was conducted in adherence to a methodological framework comprising 4 distinct stages: conceptualizing a comprehensive search strategy, screening relevant publications, extracting pertinent data, and organizing and synthesizing the resultant findings. The search used electronic databases, including MEDLINE, Embase, and Google Scholar, to ensure an exhaustive survey of the available literature.

Results

The database search yielded 150 articles, including systematic reviews, registered trials, and peer-reviewed studies, of which 48 duplicates were removed. Following the title/abstract screening, 36 publications were included in the full-text review. On completion of the full-text review, using the inclusion/exclusion criteria, 29 articles were excluded and 7 remained for data extraction and qualitative synthesis.

Main Conclusion

Existing research provides promising insights into the benefits of low-dose testosterone therapy, typically combined with estrogen therapy. These benefits may include positive impacts on body composition, functional capacity, insulin sensitivity, inflammatory markers, and cholesterol. However, there remains a substantial lack of knowledge surrounding the effects and mechanisms behind testosterone therapy in postmenopausal women in relation to its impacts on cardiovascular risk. High-quality, evidence-based clinical intervention research is needed to investigate testosterone therapy's potential implication on cardiovascular risk factors in post-menopausal women.

Cardiovascular Safety and Benefits of Testosterone Implant Therapy in Postmenopausal Women: Where Are We?

We discuss the CV safety and efficacy data for subcutaneous testosterone therapy (STT) in postmenopausal women. We also highlight new directions and applications of correct dosages performed in a specialized center. To recommend STT, we propose innovative criteria (IDEALSTT) according to total testosterone (T) level, carotid artery intima-media thickness, and calculated SCORE for a 10-year risk of fatal cardiovascular disease (CVD). Despite all the controversies, hormone replacement therapy (HRT) with T has gained prominence in treating pre and postmenopausal women in the last decades. HRT with silastic and bioabsorbable testosterone hormone implants has gained prominence recently due to its practicality and effectiveness in treating menopausal symptoms and hypoactive sexual desire disorder. A recent publication on the complications of STT, looking at a large cohort of patients over seven years, demonstrated its long-term safety. However, the cardiovascular (CV) risk and safety of STT in women are still controversial.

Sex-Specific Association between Antioxidant Defense System and Therapeutic Response to Risperidone in Schizophrenia: A Prospective Longitudinal Study

BACKGROUND

There are various differences in response to different antipsychotics and antioxidant defense systems (ADS) by sex. Previous studies have shown that several ADS enzymes are closely related to the treatment response of patients with antipsychotics-naïve first-episode (ANFE) schizophrenia.

OBJECTIVE

Therefore, the main goal of this study was to assess the sex difference in the relationship between changes in ADS enzyme activities and risperidone response.

METHODS

The plasma activities of glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD), and total antioxidant status (TAS) were measured in 218 patients and 125 healthy controls. Patients were treated with risperidone for 3 months, and we measured PANSS for psychopathological symptoms and ADS biomarkers at baseline and at the end of 3 months of treatment. We compared sex-specific group differences between 50 non-responders and 168 responders at baseline and at the end of the three months of treatment.

RESULTS

We found that female patients responded better to risperidone treatment than male patients. At baseline and 3-month follow-up, there were no significant sex differences in TAS levels and three ADS enzyme activities. Interestingly, only in female patients, after 12 weeks of risperidone treatment, the GPx activity of responders was higher than that of non-responders.

CONCLUSION

These results indicate that after treatment with risperidone, changes in GPx activity were associated with treatment response, suggesting that changes in GPx may be a predictor of response to risperidone treatment in female patients with ANFE schizophrenia.

Non-genetic influences on lipoprotein(a) concentrations

An elevated level of lipoprotein(a) [Lp(a)] is a genetically regulated, independent, causal risk factor for cardiovascular disease. However, the extensive variability in Lp(a) levels between individuals and population groups cannot be fully explained by genetic factors, emphasizing a potential role for non-genetic factors. In this review, we provide an overview of current evidence on non-genetic factors influencing Lp(a) levels with a particular focus on diet, physical activity, hormones and certain pathological conditions. Findings from randomized controlled clinical trials show that diets lower in saturated fats modestly influence Lp(a) levels and often in the opposing direction to LDL cholesterol. Results from studies on physical activity/exercise have been inconsistent, ranging from no to minimal or moderate change in Lp(a) levels, potentially modulated by age and the type, intensity, and duration of exercise modality. Hormone replacement therapy (HRT) in postmenopausal women lowers Lp(a) levels with oral being more effective than transdermal estradiol; the type of HRT, dose of estrogen and addition of progestogen do not modify the Lp(a)-lowering effect of HRT. Kidney diseases result in marked elevations in Lp(a) levels, albeit dependent on disease stages, dialysis modalities and apolipoprotein(a) phenotypes. In contrast, Lp(a) levels are reduced in liver diseases in parallel with the disease progression, although population studies have yielded conflicting results on the associations between Lp(a) levels and nonalcoholic fatty liver disease. Overall, current evidence supports a role for diet, hormones and related conditions, and liver and kidney diseases in modifying Lp(a) levels.

Characterizing skeletal muscle dysfunction in women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine condition affecting women. It has traditionally been viewed as a primarily reproductive disorder; however, it is increasingly recognized as a lifelong metabolic disease. Women with PCOS are at increased risk of insulin resistance (IR), type 2 diabetes mellitus, non-alcoholic fatty liver disease and cardiovascular disease. Although not currently a diagnostic criterion, IR is a cardinal pathophysiological feature and highly prevalent in women with PCOS. Androgens play a bidirectional role in the pathogenesis of IR, and there is a complex interplay between IR and androgen excess in women with PCOS. Skeletal muscle has a key role in maintaining metabolic homeostasis and is also a metabolic target organ of androgen action. Skeletal muscle is the organ responsible for the majority of insulin-mediated glucose disposal. There is growing interest in the relationship between skeletal muscle, androgen excess and mitochondrial dysfunction in the pathogenesis of metabolic disease in PCOS. Molecular mechanisms underpinning defects in skeletal muscle dysfunction in PCOS remain to be elucidated, but may represent promising targets for future therapeutic intervention. In this review, we aim to explore the role of skeletal muscle in metabolism, focusing particularly on perturbations in skeletal muscle specific to PCOS as observed in recent molecular and in vivo human studies. We review the possible role of androgens in the pathophysiology of skeletal muscle abnormalities in PCOS, and identify knowledge gaps, areas for future research and potential therapeutic implications. Despite increasing interest in the area of skeletal muscle dysfunction in women with PCOS, significant challenges and unanswered questions remain, and going forward, novel innovative approaches will be required to dissect the underlying mechanisms.

How the love of muscle can break a heart: Impact of anabolic androgenic steroids on skeletal muscle hypertrophy, metabolic and cardiovascular health

It is estimated 6.4% of males and 1.6% of females globally use anabolic-androgenic steroids (AAS), mostly for appearance and performance enhancing reasons. In combination with resistance exercise, AAS use increases muscle protein synthesis resulting in skeletal muscle hypertrophy and increased performance. Primarily through binding to the androgen receptor, AAS exert their hypertrophic effects via genomic, non-genomic and anti-catabolic mechanisms. However, chronic AAS use also has a detrimental effect on metabolism ultimately increasing the risk of cardiovascular disease (CVD). Much research has focused on AAS effects on blood lipids and lipoproteins, with abnormal concentrations of these associated with insulin resistance, hypertension and increased visceral adipose tissue (VAT). This clustering of interconnected abnormalities is often referred as metabolic syndrome (MetS). Therefore, the aim of this review is to explore the impact of AAS use on mechanisms of muscle hypertrophy and markers of MetS. AAS use markedly decreases high-density lipoprotein cholesterol (HDL-C) and increases low-density lipoprotein cholesterol (LDL-C). Chronic AAS use also appears to cause higher fasting insulin levels and impaired glucose tolerance and possibly higher levels of VAT; however, research is currently lacking on the effects of AAS use on glucose metabolism. While cessation of AAS use can restore normal lipid levels, it may lead to withdrawal symptoms such as depression and hypogonadism that can increase CVD risk. Research is currently lacking on effective treatments for withdrawal symptoms and further long-term research is warranted on the effects of AAS use on metabolic health in males and females.

rTMS and tDCS for the treatment of catatonia: A systematic review

BACKGROUND

Catatonia is a potentially life threatening syndrome in various psychiatric disorders. As first line treatment, benzodiazepines and electroconvulsive therapy (ECT) are recommended. In some cases, benzodiazepines are ineffective and ECT is not available or contraindicated. Therefore, the search for new and alternative treatment strategies is of great importance.

OBJECTIVE

To review the evidence for alternative neurostimulation treatment strategies (rTMS and tDCS) for catatonia according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines.

METHOD

We performed a systematic literature search in several electronic databases. We also searched the WHO International Clinical Trials Registry Platform (ICTRP) and the ClinicalTrials.gov database to detect registered studies.

RESULTS

We identified nine publications on rTMS treatment and four publications on tDCS in catatonia. Most of the publications reported clinically relevant improvement of catatonic symptoms. Only two publications reported insufficient improvement. The available Bush-Francis Catatonia Rating Scale scores showed statistical significant improvement following rTMS and tDCS. We could not identify any finished clinical studies or case series, dedicated to this topic. We also could not identify any publications that compared first line treatment options with rTMS or tDCS.

CONCLUSIONS

Based on the case report literature, rTMS and tDCS might be promising alternative treatment strategies for patients who do not respond to benzodiazepines or in case ECT is not available or contraindicated. There are even hints that rTMS or tDCS might be an option in patients who respond to ECT but need long-term treatment to control catatonic symptoms. Further clinical trials are needed to allow for an evidence-based evaluation of potential risks and benefits of rTMS and tDCS for catatonia.

Do we need sex-oriented clinical practice guidelines for the treatment of schizophrenia?

PURPOSE OF REVIEW

Clinical practice guidelines (CPGs) do not usually offer a sex-specific approach for the management of schizophrenia. With this narrative review, we aim to give an integrated and synthesized overview of the current state of knowledge regarding sex-specific aspects in schizophrenia and how this topic may be adapted in the development of CPGs.

RECENT FINDINGS

Recent studies further suggest sex-specific differences in epidemiologic features, the course of illness, underlying pathomechanisms, response likelihood to antipsychotic medication and differences in tolerability. Beyond this, selective estrogen receptor modulators like raloxifene have shown beneficial effects on symptom severity and cognition in women with schizophrenia.

SUMMARY

Sex-specific aspects can already be integrated in clinical guideline recommendations, especially with regard to efficacy and tolerability of antipsychotic treatment. Moreover, these aspects may be used for an individual risk-stratification. Recent studies provide evidence supporting the hypothesis of sex-specific modulation in schizophrenia and build the groundwork for sex-specific novel treatment options. However, there remains a clear need for additional studies focusing on women with schizophrenia to substantiate current findings.

A systematic review of randomized controlled trials investigating the efficacy and safety of testosterone therapy for female sexual dysfunction in postmenopausal women

The clinical sequelae of oestrogen deficiency during menopause are undoubted. However, the pathophysiological role of testosterone during the menopause is less clear. Several randomized, placebo-controlled clinical trials suggest that testosterone therapy improves sexual function in postmenopausal women. Some studies suggest that testosterone therapy has additional effects, which include increased bone mineral density and decreased serum high-density lipoprotein (HDL) cholesterol. Furthermore, the long-term safety profile of testosterone therapy in postmenopausal women is not clear. This article will provide a concise and critical summary of the literature, to guide clinicians treating postmenopausal women.

Sex-specific effects of dehydroepiandrosterone (DHEA) on bone mineral density and body composition: A pooled analysis of four clinical trials

OBJECTIVE

Studies of dehydroepiandrosterone (DHEA) therapy in older adults suggest sex-specific effects on bone mineral density (BMD) and body composition, but the ability of a single study to reach this conclusion was limited. We evaluated the effects of DHEA on sex hormones, BMD, fat mass and fat-free mass in older women and men enrolled in four similar clinical trials.

DESIGN

Pooled analyses of data from four double-blinded, randomized controlled trials.

PARTICIPANTS

Women (n = 295) and men (n = 290) aged 55 years or older who took DHEA or placebo tablet daily for 12 months.

MEASUREMENTS

Twelve-month changes in BMD, fat mass, fat-free mass and serum DHEA sulphate (DHEAS), (17)estradiol, testosterone and insulin-like growth factor-1 (IGF-1).

RESULTS

Women on DHEA had increases (mean ± SD; all P < 0.001 vs placebo) in DHEAS (231 ± 164 µg/dL), testosterone (18.6 ± 20.9 µg/dL), (17)estradiol (8.7 ± 11.0 pg/mL) and IGF-1 (25.1 ± 52.3 ng/mL), and men had increases in DHEAS (269.0 ± 177 µg/dL; P < 0.01), (17)estradiol (4.8 ± 12.2 pg/m; P < 0.01) and IGF-1 (6.3 ± 41.4 ng/mL; P < 0.05). Women on DHEA had increases in lumbar spine (1.0% ± 3.4%) and trochanter (0.5% ± 3.8%) BMD and maintained total hip BMD (0.0% ± 2.8%); men had no BMD benefit and a decrease in fat mass (-0.4 ± 2.6 kg; all P < 0.01 vs placebo).

CONCLUSIONS

Dehydroepiandrosterone therapy may be an effective approach for preserving bone and muscle mass in women. Key questions are (a) the extent to which longer duration DHEA can attenuate the loss of bone and muscle in women, and (b) whether DHEA has a more favourable benefit-to-risk profile for women than oestrogen therapy.

Metabolic inflexibility in women with PCOS is similar to women with type 2 diabetes

Background

An ability to switch between primarily oxidizing fat in the fasted state to carbohydrate in the fed state, termed metabolic flexibility, is associated with insulin sensitivity. Metabolic flexibility has been explored previously in women with polycystic ovary syndrome (PCOS), yet the independent or synergistic contributions of androgen excess and/or insulin resistance is not yet known. Therefore, the purpose of this article was to characterize metabolic flexibility in women with PCOS compared to women of normal BMI, obesity, or type 2 diabetes (T2DM).

Methods

Eighty-six weight-stable women; thirty with either PCOS (n = 30), or fifty-six with obesity (n = 12), T2DM (n = 27), or normal BMI (n = 17) underwent a hyperinsulinemic euglycemic clamp and indirect calorimetry to measure insulin sensitivity and substrate oxidation via indirect calorimetry, respectively.

Results

All analyses were adjusted for differences in age, ethnicity, and BMI between groups. Women with PCOS were less metabolically flexible compared to healthy women with obesity (p < 0.0001), normal BMI (p < 0.0001), but after controlling for glucose disposal rate, were similar to women with T2DM (p = 0.99). When dividing women with PCOS above and below the mean cutoff for insulin resistance, the insulin resistant women with PCOS had lower rates of non-oxidative glucose metabolism (p = 0.0001), higher levels of percent free testosterone (p = 0.04), a higher free androgen index (p = 0.006), more visceral adipose tissue (p = 0.02), and were less metabolically flexible (p = 0.007).

Conclusions

Women with T2DM were as metabolically inflexible as women with PCOS. When stratifying women with PCOS into those who are metabolically flexible and inflexible, the women who are inflexible display greater amounts of visceral fat and androgen excess. The inability to alter substrate use given the physiological stimulus may lead to subsequent increases in adiposity in women with PCOS thereby further worsening the insulin resistance.

Trial registration number

Clinical Trials.gov, NCT01482286. Registered 30 November 2011.

Multiple Mechanisms Linking Type 2 Diabetes and Alzheimer's Disease: Testosterone as a Modifier

Evidence in support of links between type-2 diabetes mellitus (T2DM) and Alzheimer's disease (AD) has increased considerably in recent years. AD pathological hallmarks include the accumulation of extracellular amyloid-β (Aβ) and intracellular hyperphosphorylated tau in the brain, which are hypothesized to promote inflammation, oxidative stress, and neuronal loss. T2DM exhibits many AD pathological features, including reduced brain insulin uptake, lipid dysregulation, inflammation, oxidative stress, and depression; T2DM has also been shown to increase AD risk, and with increasing age, the prevalence of both conditions increases. In addition, amylin deposition in the pancreas is more common in AD than in normal aging, and although there is no significant increase in cerebral Aβ deposition in T2DM, the extent of Aβ accumulation in AD correlates with T2DM duration. Given these similarities and correlations, there may be common underlying mechanism(s) that predispose to both T2DM and AD. In other studies, an age-related gradual loss of testosterone and an increase in testosterone resistance has been shown in men; low testosterone levels can also occur in women. In this review, we focus on the evidence for low testosterone levels contributing to an increased risk of T2DM and AD, and the potential of testosterone treatment in reducing this risk in both men and women. However, such testosterone treatment may need to be long-term, and would need regular monitoring to maintain testosterone at physiological levels. It is possible that a combination of testosterone therapy together with a healthy lifestyle approach, including improved diet and exercise, may significantly reduce AD risk.

The amount and types of fatty acids acutely affect insulin, glycemic and gastrointestinal peptide responses but not satiety in metabolic syndrome subjects

PURPOSE

Limited clinical evidence is available on the effects of amount and types of dietary fats on postprandial insulinemic and gastrointestinal peptide responses in metabolic syndrome subjects. We hypothesized that meals enriched with designated: (1) amount of fats (50 vs 20 g), (2) fats with differing fatty acid composition (saturated, SFA; monounsaturated, MUFA or n-6 polyunsaturated fatty acids, PUFA) would affect insulinemic and gastrointestinal peptide releases in metabolic syndrome subjects.

METHODS

Using a randomized, crossover and double-blinded design, 15 men and 15 women with metabolic syndrome consumed high-fat meals enriched with SFA, MUFA or n-6 PUFA, or a low-fat/high-sucrose (SUCR) meal. C-peptide, insulin, glucose, gastrointestinal peptides and satiety were measured up to 6 h.

RESULTS

As expected, SUCR meal induced higher C-peptide (45 %), insulin (45 %) and glucose (49 %) responses compared with high-fat meals regardless of types of fatty acids (P < 0.001). Interestingly, incremental area under the curve (AUC_0-120min) for glucagon-like peptide-1 was higher after SUCR meal compared with MUFA (27 %) and n-6 PUFA meals (23 %) (P = 0.01). AUC_0-120min for glucose-dependent insulinotropic polypeptide was higher after SFA meal compared with MUFA (23 %) and n-6 PUFA meals (20 %) (P = 0.004). Significant meal x time interaction (P = 0.007) was observed for ghrelin, but not cholecystokinin and satiety.

CONCLUSIONS

The amount of fat regardless of the types of fatty acids affects insulin and glycemic responses. Both the amount and types of fatty acids acutely affect the gastrointestinal peptide release in metabolic syndrome subjects, but not satiety.

Association of free testosterone and sex hormone binding globulin with metabolic syndrome and subclinical atherosclerosis but not blood pressure in hypertensive perimenopausal women

INTRODUCTION

Data on the role of androgens as potential mediators of increasing cardiovascular risk in women at midlife are controversial. The aim of the study was to analyze the relationship of free testosterone (FT) and sex hormone binding globulin (SHBG) with blood pressure and subclinical organ damage and metabolic syndrome (MS) in middle aged hypertensive women.

MATERIAL AND METHODS

One hundred and fifty-two women with newly diagnosed arterial hypertension were included in the study. In all subjects blood pressure measurements were performed as well as echocardiographic examination with left ventricular structure and function assessment (GE Vivid 7.0), carotid ultrasound with measurement of intima-media thickness (IMT), and carotid-femoral pulse wave velocity (PWV) measurement (Sphygmocor). A fasting blood sample was taken to measure glucose and lipid concentrations. Serum testosterone and SHBG were measured. Free testosterone was calculated according to the Vermeulen formula. Metabolic syndrome was defined following the International Diabetes Federation (IDF) recommendations.

RESULTS

Free testosterone was significantly higher and SHBG lower in women with MS independently of menopausal status. The odds ratio of MS per quartile increment in FT after adjustment for covariates was 2.06 (95% CI: 1.16-3.65). There was no correlation between FT, SHBG and blood pressure. Free testosterone was associated with decreased left ventricular diastolic function (E/A ratio β = -0.19, p = 0.05) and subclinical atherosclerosis (IMT β = 0.34, p = 0.009), but not arterial stiffness.

CONCLUSIONS

Free testosterone and SHBG independently of menopause status are related to MS. Free testosterone is associated with worse metabolic profile, subclinical atherosclerosis and impaired diastolic function of the left ventricle.

Androgen levels in women with various forms of ovarian dysfunction: associations with cardiometabolic features

STUDY QUESTION

Are differences in androgen levels among women with various forms of ovarian dysfunction associated with cardiometabolic abnormalities?

SUMMARY ANSWER

Androgen levels differed substantially between women with and without ovarian dysfunction, and increased androgen levels were associated with impaired cardiometabolic features in all women irrespective of their clinical condition.

WHAT IS KNOWN ALREADY

Sex steroid hormones play important roles in the development of cardiovascular diseases (CVD). Extremes of low as well as high androgen levels have been associated with increased CVD risk in both men and women.

STUDY DESIGN, SIZE, DURATION

This cross-sectional study included 680 women with polycystic ovary syndrome (PCOS), premature ovarian insufficiency (POI), natural post-menopausal women (NM), or regular menstrual cycles (RC) (170 women per group).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Measurements of serum testosterone, androstenedione and dehydroepiandrosterone sulfate were performed using liquid chromatography-tandem mass spectrometry. Assessments were taken of body mass index (BMI), blood pressure, lipid profiles, glucose, insulin and SHBG, and the bioactive fraction of circulating testosterone was calculated using the free androgen index (FAI).

MAIN RESULTS AND THE ROLE OF CHANCE

PCOS women were hyperandrogenic [median FAI = 4.9 (IQR 3.6-7.4)], and POI women were hypoandrogenic [FAI = 1.2 (0.8-1.7)], compared with RC women [FAI = 1.7 (1.1-2.8)], after adjustment for age, ethnicity, smoking and BMI (P < 0.001). After adjustment for age, there were no significant differences in androgens between POI and NM (P = 0.15) women and between NM and RC (P = 0.27) women, the latter indicating that chronological aging rather than ovarian aging influences the differences between pre- and post-menopausal women. A high FAI was associated with elevated triglycerides (β log FAI for PCOS: 0.45, P < 0.001, POI: 0.25, P < 0.001, NM: 0.20, P = 0.002), insulin (β log FAI for PCOS: 0.77, POI: 0.44, NM: 0.40, all P < 0.001), HOMA-IR (β log FAI for PCOS: 0.82, POI: 0.46, NM: 0.47, all P < 0.001) and mean arterial pressure (β log FAI for PCOS: 0.05, P = 0.002, POI: 0.07, P < 0.001, NM: 0.04, P = 0.04) in all women; with increased glucose (β log FAI for PCOS: 0.05, P = 0.003, NM: 0.07, P < 0.001) and decreased high-density lipoprotein (β log FAI for PCOS: -0.23, P < 0.001, NM: -0.09, P = 0.03) in PCOS and NM women; and with increased low-density lipoprotein (β log FAI for POI: 0.083, P = 0.041) in POI women. Adjustment for BMI attenuated the observed associations. Associations between FAI and cardiometabolic features were the strongest in PCOS women, even after adjustment for BMI.

LIMITATIONS, REASONS FOR CAUTION

Associations between androgen levels and cardiometabolic features were assessed in PCOS, POI and NM women only, due to a lack of available data in RC women. Due to the cross-sectional design of the current study, the potential associations between androgen levels and actual future cardiovascular events could not be assessed.

WIDER IMPLICATIONS OF THE FINDINGS

This study affirms the potent effect of androgens on cardiometabolic features, indicating that androgens should indeed be regarded as important denominators of women's health. Future research regarding the role of androgens in the development of CVD and potential modulatory effects of BMI is required.

STUDY FUNDING/COMPETING INTERESTS

N.M.P.D. is supported by the Dutch Heart Foundation (grant number 2013T083). L.J. and O.H.F. work in ErasmusAGE, a center for aging research across the life course, funded by Nestlé Nutrition (Nestec Ltd), Metagenics Inc. and AXA. M.K. is supported by the AXA Research Fund. Nestlé Nutrition (Nestec Ltd), Metagenics Inc. and AXA had no role in the design and conduct of the study; the collection, management, analysis and interpretation of the data; or the preparation, review or approval of the manuscript. J.S.E.L. has received fees and grant support from the following companies (in alphabetical order): Ferring, Merck-Serono, Merck Sharpe & Dome, Organon, Schering Plough and Serono. In the last 5 years, B.C.J.M.F. has received fees and grant support from the following companies (in alphabetic order); Actavis, COGI, Euroscreen, Ferring, Finox, Genovum, Gedeon-Richter, Merck-Serono, OvaScience, Pantharei Bioscience, PregLem, Roche, Uteron and Watson laboratories. With regard to potential conflicts of interest, there is nothing further to disclose.

The safety of testosterone therapy in women

Hypoactive sexual desire disorder (HSDD), a subset of female sexual dysfunction, causes personal distress for surgically and naturally postmenopausal and premenopausal women. HSDD has a multi-factorial etiology, including psychosocial factors such as relationship issues and medical factors such as medications, chronic illnesses, and hormonal effects. Although no androgen therapies for female sexual dysfunction are currently approved for use in Canada, clinical trials support the efficacy and short-term safety of testosterone therapy for HSDD. We review the scientific evidence for the safety of testosterone therapy for HSDD.

Androgen treatment of postmenopausal women

Testosterone is physiologically important for women. Serum testosterone levels decline with age, with the most precipitous fall being prior to menopause. There is no level of testosterone which defines a woman as being testosterone deficient. However, there is substantial high quality evidence to support the use of testosterone for the treatment of hypoactive sexual desire disorder in postmenopausal women. Although preliminary data suggests testosterone has favorable effects on bone and muscle mass, cognitive function and the cardiovascular system, further research regarding its therapeutic effects in these domains is warranted. As no testosterone product has been approved for women there is extensive off-label prescribing of testosterone products for women as well as the prescription of compounded therapy. This raises serious safety concerns and together with the evidence for the negative impact of FSD on quality of life, highlights the need for an approved testosterone formulation for women. This article is part of a Special Issue entitled 'Menopause'.

Testosterone dose-response relationships with cardiovascular risk markers in androgen-deficient women: a randomized, placebo-controlled trial

OBJECTIVE

To determine dose-dependent effects of T administration on cardiovascular risk markers in women with low T levels.

METHODS

Seventy-one hysterectomized women with or without oophorectomy with total T < 31 ng/dL and/or free T < 3.5 pg/mL received a standardized transdermal estradiol regimen during the 12-week run-in period and were then randomized to receive weekly im injections of placebo or 3-, 6.25-, 12.5-, or 25-mg T enanthate for 24 weeks. Total and free T levels were measured by liquid chromatography-tandem mass spectrometry and equilibrium dialysis, respectively. Insulin resistance and inflammatory markers were measured at baseline and 24 weeks. In a subset of women, magnetic resonance imaging of the abdomen was performed to quantify abdominal fat volume.

RESULTS

Fifty-nine women who completed the 24-week intervention were included in the final analysis. The five groups were similar at baseline. Mean on-treatment nadir total T concentrations were 14, 79, 105, 130, and 232 ng/dL in the placebo group and the 3-, 6.25-, 12.5-, and 25-mg groups, respectively. No significant changes in fasting glucose, fasting insulin, homeostatic model assessment of insulin resistance, high sensitivity C-reactive protein, adiponectin, blood pressure, and heart rate were observed at any T dose when compared to placebo. Similarly, no dose- or concentration-dependent changes were observed in abdominal fat on magnetic resonance imaging.

CONCLUSION

Short-term T administration over a wide range of doses for 24 weeks in women with low T levels was not associated with worsening of cardiovascular risk markers.

Androgens inhibit adipogenesis during human adipose stem cell commitment to preadipocyte formation

Androgens play a pivotal role in the regulation of body fat distribution. Adipogenesis is a process whereby multipotent adipose stem cells (ASCs) initially become preadipocytes (ASC commitment to preadipocytes) before differentiating into adipocytes. Androgens inhibit human (h) subcutaneous (SC) abdominal preadipocyte differentiation in both sexes, but their effects on hASC commitment to preadipocyte formation is unknown. We therefore examined whether androgen exposure to human (h) ASCs, isolated from SC abdominal adipose of nonobese women, impairs their commitment to preadipocyte formation and/or subsequent differentiation into adipocytes. For this, isolated hASCs from SC abdominal lipoaspirate were cultured in adipogenesis-inducing medium for 0.5-14days in the presence of testosterone (T, 0-100nM) or dihydrotestosterone (DHT, 0-50nM). Adipogenesis was determined by immunofluorescence microscopy and by quantification of adipogenically relevant transcriptional factors, PPARγ, C/EBPα and C/EBPβ. We found that a 3-day exposure of hASCs to T (50nM) or DHT (5nM) in adipogenesis-inducing medium impaired lipid acquisition and decreased PPARγ, C/EBPα and C/EBPβ gene expression. The inhibitory effects of T and DHT at this early-stage of adipocyte differentiation, were partially and completely reversed by flutamide (F, 100nM), respectively. The effect of androgens on hASC commitment to a preadipocyte phenotype was examined via activation of Bone Morphogenic Protein 4 (BMP4) signaling. T (50nM) and DHT (5nM) significantly inhibited the stimulatory effect of BMP4-induced ASC commitment to the preadipocyte phenotype, as regards PPARγ and C/EBPα gene expression. Our findings indicate that androgens, in part through androgen receptor action, impair BMP4-induced commitment of SC hASCs to preadipocytes and also reduce early-stage adipocyte differentiation, perhaps limiting adipocyte numbers and fat storage in SC abdominal adipose.

Ethnic- and sex-specific associations between plasma fatty acids and markers of insulin resistance in healthy young adults

BACKGROUND

Although evidence indicates that fatty acids (FA) can affect insulin resistance (IR), not all FA contribute equally to the process. Indeed, monounsaturated FA (MUFA) and polyunsaturated FA (PUFA) are reported to reduce IR, whereas saturated FA (SFA) and trans FA appear to increase IR. However, it is not yet clear how individual FA are associated with markers of IR, and whether these relationships are influenced by ethnicity and/or sex. Therefore, the goal of this study was to examine the ethnic- and sex-specific relationships between plasma FA and markers of IR in a cohort of healthy young Caucasian, East Asian, and South Asian adults.

METHODS

Gas chromatography was used to quantify fasting plasma FA from young Canadian adults (22.6 ± 0.1 yrs) of Caucasian (n = 461), East Asian (n = 362), or South Asian (n = 104) descent. Linear regression models were used to investigate associations between plasma FA and markers of IR (i.e. fasting insulin, glucose, and HOMA-IR) according to ethnicity and sex.

RESULTS

Numerous significant associations (P < 0.05, adjusted for multiple testing) were identified between individual FA and markers of IR, with the majority identified in Caucasians. For SFA, positive associations were found between 14:0 and fasting insulin and HOMA-IR in Caucasian and East Asian populations, and 18:0 and fasting glucose in Caucasians only. Several positive associations were also found for specific MUFA (18:1t11 and 18:1t6-8 with HOMA-IR, and 18:1c9 with fasting glucose) and PUFA (18:2n6 with fasting glucose and 18:2c9t11 with HOMA-IR) in Caucasian adults only. Most of the aforementioned associations were stronger in males compared to females. Interestingly, no significant associations were found between FA and markers of IR in South Asian adults.

CONCLUSIONS

We report numerous associations between plasma FA and markers of IR in Caucasian and East Asian populations, but not in South Asian individuals. Furthermore, these associations appeared to be more robust in men. This demonstrates the importance of investigating associations between FA and markers of IR in an ethnic- and sex-specific manner in order to better understand the contribution of plasma FA to the development of IR and type-2 diabetes.

Improvement of the lipid profile in post menopausal women who use estradiol and testosterone implants

OBJECTIVE

This study evaluating the lipid profile in women in post menopause using the hormone therapy (HT) with implants of estradiol and testosterone.

METHOD

One year prospective cohort with 122 patients separated in group 1, not using HT, group 2 starting the use of HT, and group 3 with prior use of implants of estradiol and testosterone. All patients performed serum dosages of total cholesterol, HDL and triglycerides, in the beginning of the study and after 1 year.

DISCUSSION

The use of E and T implants showed some statistically significant decrease in TC at the beginning of the HT and some decrease in LDL in the group using HT. In the group without HT there was no difference in lipid profile.

Androgen replacement therapy in women

Female androgens are derived from either the adrenal and peripheral conversion of the adrenal sex steroid precursor, dehydroepiandrosterone, or from direct ovarian production. Adrenal insufficiency or bilateral oophorectomy (surgical menopause) result in severe androgen deficiency, which can be clinically associated with impaired libido, drive and energy. Physiological menopause does not necessarily lead to androgen deficiency. The previously suggested definition of female androgen deficiency syndrome, as the concurrent presence of low androgen levels and low libido, is not precise enough and may lead to overdiagnosis. Current replacement options include transdermal testosterone or oral dehydroepiandrosterone treatment, both of which have been shown to result in significant improvements, in particular in libido and mood, while long-term effects on body composition, cardiovascular and cancer risk are less documented. Owing to these concerns, androgen replacement should be reserved for women with severe androgen deficiency due to an established cause and matching clinical symptoms.

The safety of postmenopausal testosterone therapy

Testosterone is increasingly used as part of postmenopausal HRT regimens. Unfortunately, few androgenic preparations designed specifically for use in women have been approved by regulatory authorities. Ongoing concerns exist surrounding the potential long-term effects of testosterone therapy. Here, we review the most recent data on postmenopausal testosterone therapy, focusing particularly on the effects of testosterone on breast, endometrium and cardiovascular health.

Effects of oestrogen and testosterone therapy on serum metabolites in postmenopausal women

OBJECTIVES

Metabolite profiles of body fluids or tissue extracts can be regarded as important indicators of physiological or pathological states. Whether hormone-specific alterations of the serum metabolome can be identified using this technique has not been tested yet. The aim of this study was to investigate metabolic responses during hormone therapy in postmenopausal women by a nontargeted metabolomics approach.

METHODS

Sixty naturally postmenopausal women were randomly assigned to treatment with testosterone undecanoate 40 mg every second day; estradiol valerate 2 mg daily; or the combination of both. Serum metabolites were determined by gas chromatography-mass spectrometry (GC-MS) before and after 3 months of treatment. Metabolites affected by the treatment were identified and correlated with changes in insulin sensitivity and lipid profiles.

RESULTS

Treatment-dependent and hormone-specific effects on serum metabolites were observed, ranging between 69% reduction and 184% increase, but the metabolites that best explained the differences could not be structurally identified. Effects on annotated metabolites were less associated with clinical parameters as compared to established serum markers for adverse lipid and carbohydrate metabolism, such as cholesterol and triglycerides. However, cystine, lysine and tyrosine were shown to change in correlation with insulin sensitivity and high-density lipoprotein cholesterol levels in response to testosterone, indicating that those responses were somehow related to each other.

CONCLUSIONS

Oestrogen- and androgen-specific alterations in the serum metabolome could be identified using GC-MS, reflecting hormone-specific effects on whole body metabolism. New knowledge regarding steroid-mediated metabolic responses within different tissues might be obtained using a similar approach on tissue extracts.

Androgen levels and metabolic parameters are associated with a genetic variant of F13A1 in women with polycystic ovary syndrome

The polycystic ovary syndrome (PCOS), characterized by hyperandrogenism, is one of the most common hormonal disorders among premenopausal women and is associated with infertility, obesity, and insulin resistance. Accumulating evidence suggests a role of the blood coagulation factor gene F13A1 in obesity (GeneBank ID: NM_000129.3). The aim of this study was to investigate the association of intronic allelic variants of the F13A1 gene with PCOS susceptibility and metabolic parameters in lean and obese PCOS women. In a case-control study, we determined an intronic F13A1 single nucleotide polymorphism (SNP) (dbSNP ID: rs7766109) in 585 PCOS and 171 control women and tested for PCOS susceptibility and associations with anthropometric, metabolic and hormonal parameters. Genotype frequencies of the F13A1 SNP rs7766109 were equivalent in PCOS and control women. In PCOS women, F13A1 gene variants were significantly associated with body mass index (BMI) (p=0.013), systolic blood pressure (p=0.042), insulin response (AUCins) (p=0.015), triglycerides (TG) (p=0.001), and high density lipoprotein cholesterol (HDL) (p=0.012). In the subgroup of obese PCOS women free androgen index (FAI), free testosterone and sex hormone binding globulin (SHBG) as well as glucose measurements showed a significantly different pattern across F13A1 gene variants (p=0.043; p=0.039 and p=0.013, respectively). We report for the first time an association of the F13A1 SNP rs7766109 with BMI, androgens, and insulin resistance in PCOS women. Further studies are needed to confirm our findings and to evaluate whether F13A1 is causally involved in the pathogenesis of PCOS related metabolic and hormonal disturbances.

The role of androgens and estrogens on healthy aging and longevity

Aging is associated with a loss of sex hormone in both men (andropause) and women (menopause). In men, reductions in testosterone can trigger declines in muscle mass, bone mass, and in physical function. In women, the impact of the loss of sex hormones, such as estradiol, on bone is well elucidated, but evidence is limited on whether the loss of estradiol negatively affects muscle mass and physical function. However, deficiencies in multiple anabolic hormones have been shown to predict health status and longevity in older persons. Thus, consideration should be given as to whether targeted hormone replacement therapies may prove effective at treating clinical conditions, such as age-related sarcopenia, cancer cachexia, and/or acute or chronic illnesses. If initiated carefully in the appropriate clinical population, hormone replacement therapies in men and women may prevent and reverse muscle and bone loss and functional declines and perhaps promote healthy aging and longevity.

Sex hormones, appetite and eating behaviour in women

Sex hormones play essential roles in the regulation of appetite, eating behaviour and energy metabolism and have been implicated in several major clinical disorders in women. Estrogen inhibits food intake, whereas progesterone and testosterone may stimulate appetite. This review describes recent findings concerning interactions between sex hormones and neuroendocrinological mechanisms in the control of appetite and eating in women. Furthermore, we are gaining insights into the roles played by sex hormones in the development of eating disorders and obesity. For instance, androgens may promote bulimia by stimulating appetite and reducing impulse control, a proposal supported by the observation that antiandrogenic treatment attenuates bulimic behaviour. Androgens are also involved in the pathophysiology of abdominal obesity in women. On the other hand, hormone replacement therapy with estrogen counteracts the weight gain and accumulation of abdominal fat associated with the menopausal transition. In conclusion, sex hormones and/or agents that exhibit similar activities may provide novel strategies for the treatment of eating disorders and android obesity, two of the most serious health problems for women today.

Cardiovascular disease and primary ovarian insufficiency

Cardiovascular disease (CVD) is the number-one killer of women. Women with primary ovarian insufficiency (POI) may be more burdened by cardiovascular disease, such as myocardial infarction and stroke, as compared with women with normal menopause. The increased burden may be mediated by a worsening of cardiovascular risk factors, such as lipids, corresponding with the loss of ovarian function. In contrast, the increased burden may be caused by factors that precede and potentially contribute to both CVD events and ovarian decline, such as X-chromosome abnormalities and smoking. Regardless of the cause, women with POI may serve as an important population to target for CVD screening and prevention strategies. These strategies should include the use of CVD risk stratification tools to identify women that may benefit from lifestyle modification and pharmacological therapy to prevent CVD. Sex steroid therapy for the sole purpose of CVD prevention in women with POI cannot be recommended, based on a lack of evidence.

Experimentally induced gestational androgen excess disrupts glucoregulation in rhesus monkey dams and their female offspring

Discrete fetal androgen excess during early gestation in rhesus monkeys (Macaca mulatta) promotes endocrine antecedents of adult polycystic ovary syndrome (PCOS)-like traits in female offspring. Because developmental changes promoting such PCOS-like metabolic dysfunction remain unclear, the present study examined time-mated, gravid rhesus monkeys with female fetuses, of which nine gravid females received 15 mg of testosterone propionate (TP) subcutaneously daily from 40 to 80 days (first to second trimesters) of gestation [term, mean (range): 165 (155-175) days], whereas an additional six such females received oil vehicle injections over the same time interval. During gestation, ultrasonography quantified fetal growth measures and was used as an adjunct for fetal blood collections. At term, all fetuses were delivered by cesarean section for postnatal studies. Blood samples were collected from dams and infants for glucose, insulin, and total free fatty acid (FFA) determinations. TP injections transiently accelerated maternal weight gain in dams, very modestly increased head diameter of prenatally androgenized (PA) fetuses, and modestly increased weight gain in infancy compared with concurrent controls. Mild to moderate glucose intolerance, with increased area-under-the-curve circulating insulin values, occurred in TP-injected dams during an intravenous glucose tolerance test in the early second trimester. Moreover, reduced circulating FFA levels occurred in PA fetuses during a third trimester intravenous glucagon-tolbutamide challenge (140 days gestation), whereas excessive insulin sensitivity and increased insulin secretion relative to insulin sensitivity occurred in PA infants during an intravenous glucose-tolbutamide test at ∼1.5 mo postnatal age. Data from these studies suggest that experimentally induced fetal androgen excess may result in transient hyperglycemic episodes in the intrauterine environment that are sufficient to induce relative increases in pancreatic function in PA infants, suggesting in this nonhuman primate model that differential programming of insulin action and secretion may precede adult metabolic dysfunction.

Reproductive hormones and obesity: 9 years of observation from the Study of Women's Health Across the Nation

The effect of change in reproductive hormones and menopause on incident obesity (body mass index > or =30 kg/m(2)) and severe obesity (body mass index > or =35 kg/m(2)) was evaluated over 9 years in 3,260 US women recruited in the multiethnic Study of Women's Health Across the Nation in 1996-1997. After 9 years, cumulative incidences of obesity and severe obesity reached 21.8% and 12.3%, respectively. In multivariate analysis, hormone changes, chronic health conditions, lower physical activity, race/ethnicity, and age were significantly associated with incident obesity and/or severe obesity. The odds of incident severe obesity increased with surgical menopause (odds ratio (OR) = 5.07, 95% confidence interval (CI): 2.29, 11.20; P < 0.001) and initiation of hormone therapy prior to 12 months of amenorrhea (OR = 2.94, 95% CI: 1.14, 7.58; P = 0.03). Predictors of obesity included an increase in free androgen index (OR = 1.37, 95% CI: 1.12, 1.68; P = 0.002) and a decrease in sex hormone-binding globulin (OR = 0.60, 95% CI: 0.45, 0.80; P = 0.0005). Similar results were found for severe obesity. Obesity rates varied by race, but no hormone-by-race interactions were observed. These longitudinal data demonstrate that higher androgens, lower sex hormone-binding globulin, surgical menopause, and early hormone therapy use predict incident obesity and/or severe obesity in a multiracial cohort of women transitioning into menopause.

Metabolic actions of insulin in men and women

Insulin is an important regulator of glucose, lipid, and protein metabolism. It suppresses hepatic glucose and triglyceride production, inhibits adipose tissue lipolysis and whole-body and muscle proteolysis, and stimulates glucose uptake in muscle. In this review we discuss what is currently known about the control of substrate metabolism by insulin in men and women. The data available so far indicate that women are more sensitive to insulin with regards to glucose metabolism (both in the liver and in muscle), whereas there are no differences between men and women in insulin action on lipolysis. Potential differences exist in the regulation of plasma triglyceride concentration and protein metabolism by insulin and in changes in insulin action in response to stimuli (e.g., weight loss and exercise) that are known to alter insulin sensitivity. However, these areas have not been studied comprehensively enough to draw firm conclusions.

Polycystic Ovary Syndrome, Obesity and Reproductive Implications

Polycystic ovary syndrome (PCOS) is one of the most common causes of female infertility, affecting 5–10% of women of reproductive age. The syndrome is characterized by anovulation, hyperandrogenism and polycystic ovaries. Furthermore, PCOS is associated with insulin resistance and obesity, which is present in approximately 50% of women with PCOS. Reproductive function in women with PCOS is strongly dependent on bodyweight and metabolic status. Obesity is associated with an increased risk of infertility and may also have a negative influence on pregnancy outcome. Considering the worldwide epidemic of obesity, clinical problems relating to PCOS may worsen and increase in frequency. Lifestyle interventions resulting in weight loss comprise the most successful strategy to improve symptoms of PCOS. However, many patients fail to lose weight or may quickly regain weight. It is an important challenge to develop effective lifestyle programs and adjuvant pharmacologic treatments in order to improve reproductive and metabolic health among women with PCOS.

Androgen replacement therapy in androgen-deficient women with hypopituitarism

Hypopituitarism is a rare disorder, but its prevalence has increased as a result of an increase in secondary causes of hypopituitarism such as traumatic brain injury and cranial irradiation. Estrogen with or without progestogen (progestin) treatment is conventional therapy in women with hypopituitarism. Recent data demonstrate that women with hypopituitarism may experience marked androgen deficiency as a consequence of secondary loss of function of the adrenal cortex and/or ovaries. This deficiency is not always considered and therefore androgen therapy is not routinely prescribed. Recent clinical trials indicate that testosterone supplementation in physiological doses for androgen-deficient women with hypopituitarism may improve psychological well-being and sexual function, and increase bone mineral density and lean body mass. Dehydroepiandrosterone (DHEA; prasterone) supplementation may be an option for women with hypopituitarism who have secondary adrenal insufficiency and low levels of DHEA and DHEA sulfate. While short-term treatment with testosterone or DHEA appears to be safe, long-term safety data are lacking. Androgenic adverse effects limit the acceptability of treatment for some women. Further studies to establish the efficacy and safety of androgen treatment for long-term intervention in a larger group of hypopituitary androgen-deficient women are needed.

Effects of androgens on insulin action in women: is androgen excess a component of female metabolic syndrome?

Hyperinsulinemia as a consequence of insulin resistance causes hyperandrogenemia in women. The objective was to review evidence for the converse situation, i.e. whether androgens adversely influence insulin action. Androgen excess could potentially contribute to the pathogenesis of insulin resistance in women with polycystic ovary syndrome (PCOS), metabolic syndrome/type 2 diabetes, and in obese peripubertal girls. An Entrez-PubMed search was conducted to identify studies addressing the relationship of androgens with metabolic syndrome/type 2 diabetes in women. Studies reporting outcomes of androgen administration, interventions to reduce androgen effects in hyperandrogenemic women, and basic studies investigating androgen effects on insulin target tissues were reviewed. Multiple studies showed associations between serum testosterone and insulin resistance or metabolic syndrome/type 2 diabetes risk in women, but their cross-sectional nature did not allow conclusions about causality. Androgen administration to healthy women was associated with development of insulin resistance. Intervention studies in women with hyperandrogenism were limited by small subject numbers and use of indirect methods for assessing insulin sensitivity. However, in three of the seven studies using euglycemic hyperinsulinemic clamps, reduction of androgen levels or blockade of androgen action improved insulin sensitivity. Testosterone administration to female rats caused skeletal muscle insulin resistance. Testosterone induced insulin resistance in adipocytes of women in vitro. In conclusion, the metabolic consequences of androgen excess in women have been under-researched. Studies of long-term interventions that lower androgen levels or block androgen effects in young women with hyperandrogenism are needed to determine whether these might protect against metabolic syndrome/type 2 diabetes in later life.

Does insulin resistance, visceral adiposity, or a sex hormone alteration underlie the metabolic syndrome? Studies in women

Insulin resistance, obesity, and a sex hormone alteration have each been suggested as the underlying link for the constellation of risk factors for myocardial infarction (MI) commonly referred to as the metabolic syndrome or the insulin resistance syndrome. In an attempt to identify in women which of these variables is the most likely link, insulin, adiposity variables, sex hormones, and risk factors for MI were measured and their relationships analyzed statistically in 58 premenopausal and 20 postmenopausal healthy women. On controlling for age, visceral adipose tissue (VAT) correlated more strongly with risk factors for MI, insulin, and free testosterone (FT) than did total adipose tissue or subcutaneous adipose tissue. VAT, therefore, was used as the adiposity variable for further data analysis. Waist circumference was a better surrogate of VAT than was waist-hip ratio, which was a poor surrogate of VAT. VAT correlated positively with insulin, FT, triglyceride, and glucose, and negatively with high-density lipoprotein and sex hormone-binding globulin. On controlling for age, FT and insulin correlated with risk factors for MI and with each other, but on controlling for age and VAT, all of their correlations lost statistical significance except for FT-triglyceride and FT-insulin in the postmenopausal women. In conclusion, VAT accumulation in women, independently of other measures of adiposity, may largely explain the correlations of insulin, obesity, and sex hormones with risk factors for MI and may be the immediate underlying factor that links risk factors for MI to form the metabolic syndrome. Insulin resistance, which has been generally accepted to be the underlying factor, may be a component of the syndrome rather than its underlying link. We hypothesize that in women FT may effect preferential VAT accumulation and induce insulin resistance directly, as well as via VAT accumulation, so that a sex hormone alteration may underlie VAT accumulation and thus ultimately underlie the metabolic syndrome (with insulin resistance as a component).

Key lipogenic gene expression can be decreased by estrogen in human adipose tissue

OBJECTIVE

To characterize the molecular mechanisms by which estrogens reduce adipose tissue mass, with particular focus on genes involved in lipogenesis.

DESIGN

This study involves one arm of an open randomized clinical study with parallel group comparison.

SETTING

Women's health clinical research unit at a university hospital and a university research laboratory.

PATIENT(S)

Samples from ten naturally postmenopausal women are included in the study.

INTERVENTION(S)

The participants were studied before and after 3 months of treatment with estradiol valerate (2 mg daily).

MAIN OUTCOME MEASURE(S)

Affymetrix gene chips were used to study changes in gene expression upon estrogen treatment in subcutaneous abdominal adipose tissue.

RESULT(S)

Genes involved in fatty acid synthesis, such as stearoyl-CoA desaturase, fatty acid synthase, acetyl-coenzyme A carboxylase alpha, and fatty acid desaturase 1 were decreased by estrogen treatment in a subgroup of women. Changes in the expression of these genes were correlated to changes in plasma triglyceride levels. Another gene decreased by estrogen treatment was peroxisome proliferator activated receptor gamma (PPARG).

CONCLUSION(S)

Key lipogenic genes and the important adipogenic gene PPARG can be regulated by estrogen in human abdominal adipose tissue, which could be relevant for increased adiposity following menopause.

Effects of sex hormone levels on aortic vascular reactivity and variables associated with the metabolic syndrome in sucrose-fed female rats

We studied the effect of varying levels of sex hormones, induced by ovariectomy and administration of testosterone or estradiol, on aortic reactivity in female rats with metabolic syndrome (MS) induced by a sucrose diet. Vasoreactivity of aortic rings, blood pressure, intra-abdominal fat, serum triglycerides, nitrates and nitrites, and TBARS were evaluated. Intact MS and ovariectomized MS had higher BP than intact control (C) and ovariectomized C, respectively; estradiol administration decreased BP in ovariectomized MS but not in ovariectomized C. Triglycerides and fat were both higher in MS. Triglycerides were not modified by surgery or hormone treatment, but ovariectomy increased fat. When ovariectomy was combined with hormones, however, fat was reduced to the level of intact rats. Ovariectomy decreased, but hormones increased, serum nitrates and nitrites. Vasoconstriction was larger in intact MS and ovariectomized MS + testosterone aortas than in intact C and ovariectomized C + testosterone, respectively. Vasodilation was reduced in intact MS and ovariectomized MS + testosterone compared with intact C, ovariectomized C + testosterone, ovariectomized MS, and ovariectomized MS + estradiol. The results suggest endothelial dysfunction in intact MS and ovariectomized MS + testosterone, but protection by ovariectomy + estradiol in MS due to hormones. Indomethacin reduced all contractions, but the effect was greater in estradiol-treated rats. l-NAME increased contractility, more in the ovariectomized C and MS groups and less in the estradiol-treated groups.

Effects of testosterone treatment on endometrial proliferation in postmenopausal women

CONTEXT

Available data concerning effects of testosterone on endometrium of postmenopausal women are seriously limited.

OBJECTIVE

Our aim was to compare the influence of treatment with testosterone and/or estrogen on endometrial proliferation in healthy postmenopausal women.

DESIGN

This was an open, randomized clinical study with parallel comparison of the groups.

SETTING

The study was conducted at a women's health clinical research unit and a research laboratory at a university hospital.

PARTICIPANTS

Sixty-three women who had experienced natural menopause participated in this study.

INTERVENTIONS

After random assignment, the participants were administered orally testosterone undecanoate (40 mg every second day), estradiol valerate (2 mg daily), or both for 3 months.

MAIN OUTCOME MEASURES

Endometrial thickness was measured, and endometrial proliferation evaluated on the basis of histopathology and expression of Ki-67, a proliferation marker.

RESULTS

Endometrial thickness was significantly increased by treatment with estrogen alone or in combination with testosterone but was unaltered by testosterone alone. Among the women receiving estrogen alone, the proportion exhibiting histopathology indicative of proliferation increased significantly to 50% (P < 0.05), there was a nonsignificant increase to 28% with the combined treatment, whereas testosterone alone had no effect at all. Expression of Ki-67 was up-regulated significantly in both glands and stroma (P < 0.05, respectively) in both estrogen treatment groups. However, the expression was significantly higher in stroma by estrogen treatment alone than after combined treatment (P < 0.05).

CONCLUSIONS

The short-term treatment with testosterone of postmenopausal women does not stimulate endometrial proliferation. In addition, testosterone appears to counteract endometrial proliferation induced by estrogen to a certain extent.