The use of a sensitive equilibrium dialysis method for the measurement of free testosterone levels in healthy, cycling women and in human immunodeficiency virus-infected women

Impacts of Anabolic-androgenic steroid supplementation on female health and offspring: Mechanisms, side effects, and medical perspectives

The increasing prevalence of Anabolic-androgenic steroids (AAS) among women, driven by the pursuit of improved body aesthetics, characterized by higher lean mass and reduced adipose tissue, raises significant health concerns, particularly due to the limited knowledge regarding their effects on the female organism. Prolonged use and/or high doses of AAS are linked to various harmful side effects, including mood changes, psychiatric disorders, voice deepening, clitoromegaly, menstrual irregularities, and cardiovascular complications, prompting medical societies to discourage their widespread use due to insufficient evidence supporting their safety and efficacy. Studies in female rodents have shown that AAS can lead to increased aggression, inflammation, reduced neuronal density, and negative impacts on the myocardium and blood vessels. Additionally, maternal administration of androgens during pregnancy can adversely affect offspring's reproductive, neuronal, and metabolic health, resulting in long-term impairments. The complexity of the mechanisms underlying AAS effects, and their potential genotoxicity remains poorly understood. This review aims to elucidate the various ways in which AAS can impact female physiology and that of their offspring, highlight commonly used anabolic substances, and discuss the positions of medical societies regarding AAS use.

Original salivary sex hormone data of naturally menstruating athletes and hormonal contraceptive users

Objectives

There is a lack of data on salivary sex hormones across the menstrual cycle (MC) or hormonal contraceptive (HC) cycle of elite athletes. We aimed to provide original data on salivary sex hormones (17β-estradiol, progesterone and free testosterone) in naturally menstruating female athletes with a regular cycle or irregular cycle and using combined HC. A secondary purpose was to compare these data with published data from the general population according to the menstrual status (MC or HC or irregularly menstruating).

Methods

367 saliva tests were performed on 44 elite athletes during 6 months of follow-up to certify for cycle regularity. Athletes were grouped into regular MC, n=13; irregular MC, n=5; and HC, n=26. We compared salivary data of regular MC across six cycle phases (menses, mid-follicular, late follicular, early luteal, mid-luteal and late luteal phases) with published data from women with a similar MC or HC status from the general population.

Results

We provided salivary original data according to six sub-phases among elite athletes with regular MC. HC athletes showed lower salivary sex hormonal levels, markedly after the first week of active HC compared with regular MC. Athletes with irregular cycles do not show a progesterone rise from the first half to the second half of the cycle (Δirregular=0.38 (1.90), a rise detectable within regular MC group ΔregularMC=2.86 (2.88)).

Conclusions

We provided original data for salivary sex hormone levels in elite female athletes. These references may be valuable for research investigating MC or combined HC data, particularly in longitudinal follow-ups requiring repeated measurements.

Blood testosterone levels in sickness and in health: Male chimpanzee testosterone levels decrease in face of an immune challenge

As an integral part of the immune response, testosterone secretion is inhibited when an individual is confronted with an immune challenge. Testosterone-mediated physiological, morphological, and behavioral traits are compromised at times of impaired health. Nevertheless, males of some species seem to maintain high levels of testosterone when confronted with an immune challenge, upholding competitive strength but compromising their immune response. It has been argued that this phenomenon will occur only in species living in social systems with high degrees of male-male competition over mating opportunities. Male chimpanzees contest over access to fertile females and dominants sire the majority of offspring. This male mating pattern makes chimpanzees a candidate species where we could expect males to maintain high testosterone levels, compromising their immune response, to ensure immediate reproductive success. We measured blood testosterone levels in male and female chimpanzees, who expressed clinical symptoms (symptomatic) or showed no evidence of clinical disease on assessment (asymptomatic). For females, we expected to find lower testosterone levels in symptomatic individuals than in asymptomatic subjects. In males, we would predict lower testosterone levels in symptomatic individuals than in asymptomatic males, if the immune response leads to a decrease in testosterone secretion. Alternatively, males could have equal levels of testosterone when symptomatic and asymptomatic, upholding competitive strength. Our results show that male chimpanzees exhibit lower levels of testosterone when confronted with an immune challenge than when being asymptomatic. This suggests that male testosterone secretion is suppressed as part of the immune response, which potentially increases survival and lifetime reproductive success. It will, however, negatively impact momentary competitive ability. Also, males may employ different mating strategies, some of which are less testosterone-driven (e.g., affiliative strategies). Consequently, in some individuals, the costs of maintaining high testosterone levels may not outweigh the potential gain in reproductive success.

Prostate-Specific Antigen Levels During Testosterone Treatment of Hypogonadal Older Men: Data from a Controlled Trial

CONTEXT

Prostate-specific antigen (PSA) changes during testosterone treatment of older hypogonadal men have not been rigorously evaluated.

DESIGN

Double-blinded, placebo-controlled trial.

SETTING

Twelve US academic medical centers.

PARTICIPANTS

Seven hundred ninety hypogonadal men ≥65 years of age with average testosterone levels ≤275 ng/dL. Men at high risk for prostate cancer were excluded.

INTERVENTIONS

Testosterone or placebo gel for 12 months.

MAIN OUTCOMES

Percentile changes in PSA during testosterone treatment of 12 months.

RESULTS

Testosterone treatment that increased testosterone levels from 232 ± 63 ng/dL to midnormal was associated with a small but substantially greater increase (P < 0.001) in PSA levels than placebo treatment. Serum PSA levels increased from 1.14 ± 0.86 ng/mL (mean ± SD) at baseline by 0.47 ± 1.1 ng/mL at 12 months in the testosterone group and from 1.25 ± 0.86 ng/mL by 0.06 ± 0.72 ng/mL in the placebo group. Five percent of men treated with testosterone had an increase ≥1.7 ng/mL and 2.5% of men had an increase of ≥3.4 ng/mL. A confirmed absolute PSA >4.0 ng/mL at 12 months was observed in 1.9% of men in the testosterone group and 0.3% in the placebo group. Four men were diagnosed with prostate cancer; two were Gleason 8.

CONCLUSIONS

When hypogonadal older men with normal baseline PSA are treated with testosterone, 5% had an increase in PSA ≥1.7 ng/mL, and 2.5% had an increase ≥3.4 ng/mL.

The effects of testosterone administration on muscle areas of the trunk and pelvic floor in hysterectomized women with low testosterone levels: proof-of-concept study

OBJECTIVE

The aim of this study was to determine the effect of testosterone administration on trunk and pelvic floor muscle area in women with low testosterone levels.

METHODS

Participants were hysterectomized women with total testosterone<31 ng/dL and/or free testosterone<3.5 pg/mL; participating in the Testosterone Dose Response in Surgically Menopausal Women (TDSM) trial. All participants received a standardized transdermal estradiol regimen during the 12-week run-in period, and were then randomized to receive weekly intramuscular injections of placebo, or 3, 6.25, 12.5, or 25 mg testosterone enanthate for 24 weeks. Muscle areas of the trunk and pelvis were measured at baseline and end of treatment using 1.5 Tesla magnetic resonance imaging. Total and free testosterone levels were measured by liquid chromatography-tandem mass spectrometry and equilibrium dialysis, respectively. Testosterone effect on muscle areas was analyzed using linear regression models.

RESULTS

A total of 24 women who had available baseline and posttreatment magnetic resonance imaging were included in the analysis. Increased cross-sectional areas of the paraspinal, psoas, and abdominal wall muscles were seen after testosterone administration. The estimated mean change (95% CI; P value) between treatment groups was 4.07 cm (1.26-6.88; P = 0.007) for paraspinal, 1.60 cm (0.10-3.09; P = 0.038) for psoas major, and 7.49 cm (1.96-13.02; P = 0.011) for abdominal wall muscles. Increases in psoas muscle area were significantly associated with changes in free testosterone concentrations. No significant changes in obturator internus and pelvic floor muscle areas were observed.

CONCLUSION

Short-term testosterone administration in women with low testosterone levels was associated with increased trunk muscle area.

Optimizing HIV prevention and care for transgender adults

: Transgender women have recently been acknowledged as a unique and important risk group in HIV research and care. Although transgender men also face specific problems related to HIV infection, less is known about the risk behaviours and HIV prevalence of this important population. This article highlights key issues relating to the epidemiology, prevention, treatment and management of complications of HIV infection in transgender adults living with HIV, and explores future areas for HIV-related research, with the ultimate goal of improving healthcare provision and quality of life for transgender persons worldwide.

A randomized trial of adjunct testosterone for cancer-related muscle loss in men and women

BACKGROUND

Cancer cachexia negatively impacts cancer-related treatment options, quality of life, morbidity, and mortality, yet no established therapies exist. We investigated the anabolic properties of testosterone to limit the loss of body mass in late stage cancer patients undergoing standard of care cancer treatment.

METHODS

A randomized, double-blind, placebo-controlled phase II clinical trial was undertaken to assess the potential therapeutic role of adjunct testosterone to limit loss of body mass in patients with squamous cell carcinoma of the cervix or head and neck undergoing standard of care treatment including chemotherapy and chemoradiation. Patients were randomly assigned in blocks to receive weekly injections of either 100 mg testosterone enanthate or placebo for 7 weeks. The primary outcome was per cent change in lean body mass, and secondary outcomes included assessment of quality of life, tests of physical performance, muscle strength, daily activity levels, resting energy expenditure, nutritional intake, and overall survival.

RESULTS

A total of 28 patients were enrolled, 22 patients were studied to completion, and 21 patients were included in the final analysis (12 placebo, nine testosterone). Adjunct testosterone increased lean body mass by 3.2% (95% confidence interval [CI], 0-7%) whereas those receiving placebo lost 3.3% (95% CI, -7% to 1%, P = 0.015). Although testosterone patients maintained more favourable body condition, sustained daily activity levels, and showed meaningful improvements in quality of life and physical performance, overall survival was similar in both treatment groups.

CONCLUSIONS

In patients with advanced cancer undergoing the early phase of standard of care therapy, adjunct testosterone improved lean body mass and was also associated with increased quality of life, and physical activity compared with placebo.

Do anabolic-androgenic steroids have performance-enhancing effects in female athletes?

Doping with anabolic-androgenic steroids (AAS) is common among both male and female athletes and is a growing public health problem. Review of historical data of systematic state-sponsored doping programs implemented by the German Democratic Republic in elite female athletes and from clinical trials of testosterone administration in non-athlete women suggests that AAS have ergogenic effects in women. The use of AAS in female athletes has been associated with adverse effects that include acne, hirsutism, deepening of the voice and menstrual disturbances; life-threatening adverse effects such as cardiac arrhythmias and sudden death have also been reported. Therefore, detection of AAS abuse in female athletes is important to ensure fairness in competition; at the same time, the athletes should be educated regarding the adverse consequences of AAS use. Although administration of exogenous androgens have been associated with ergogenic effects, it remains unclear whether endogenous hyperandrogenism seen in some medical conditions such as disorders of sexual development (DSD), congenital adrenal hyperplasia and polycystic ovary syndrome, confers any competitive advantage. Well-designed studies are needed to determine the effects of endogenous hyperandrogenism on athletic performance in female athletes.

Progesterone and Overlooked Endocrine Pathways in Breast Cancer Pathogenesis

Worldwide, breast cancer incidence has been increasing for decades. Exposure to reproductive hormones, as occurs with recurrent menstrual cycles, affects breast cancer risk, and can promote disease progression. Exogenous hormones and endocrine disruptors have also been implicated in increasing breast cancer incidence. Numerous in vitro studies with hormone-receptor-positive cell lines have provided insights into the complexities of hormone receptor signaling at the molecular level; in vivo additional layers of complexity add on to this. The combined use of mouse genetics and tissue recombination techniques has made it possible to disentangle hormone action in vivo and revealed that estrogens, progesterone, and prolactin orchestrate distinct developmental stages of mammary gland development. The 2 ovarian steroids that fluctuate during menstrual cycles act on a subset of mammary epithelial cells, the hormone-receptor-positive sensor cells, which translate and amplify the incoming systemic signals into local, paracrine stimuli. Progesterone has emerged as a major regulator of cell proliferation and stem cell activation in the adult mammary gland. Two progesterone receptor targets, receptor activator of NfκB ligand and Wnt4, serve as downstream paracrine mediators of progesterone receptor-induced cell proliferation and stem cell activation, respectively. Some of the findings in the mouse have been validated in human ex vivo models and by next-generation whole-transcriptome sequencing on healthy donors staged for their menstrual cycles. The implications of these insights into the basic control mechanisms of mammary gland development for breast carcinogenesis and the possible role of endocrine disruptors, in particular bisphenol A in this context, will be discussed below.

Relevance of low testosterone to non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a condition where there is excess accumulation of triglycerides in the liver in the absence of excess alcohol consumption. It ranges from simple steatosis to non-alcoholic steatohepatitis (NASH), which can progress to fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). NAFLD, one of the most common causes of chronic liver disease in Western populations, is the hepatic component of the metabolic syndrome (MetS) and is associated with increased visceral adipose tissue (VAT), insulin resistance, and dyslipidemia. Studies have also shown that testosterone deficiency is associated with increased VAT and insulin resistance in males while hyperandrogenemia has been associated with increased risk of insulin resistance and VAT in females. Thus, the aims of this review are to discuss the available experimental and epidemiological data evaluating the association between testosterone and NAFLD, to discuss the potential clinical relevance of these data, and to identify gaps in the literature.

Functional Voice Testing Detects Early Changes in Vocal Pitch in Women During Testosterone Administration

OBJECTIVE

To determine dose-dependent effects of T administration on voice changes in women with low T levels.

METHODS

Seventy-one women who have undergone a hysterectomy 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. Voice handicap was measured by self-report using a validated voice handicap index questionnaire at baseline and 24 weeks after intervention. Functional voice testing was performed using the Kay Elemetrics-Computer Speech Lab to determine voice frequency, volume, and harmonics.

RESULTS

Forty-six women with evaluable voice data at baseline and after intervention were included in the analysis. The five groups were similar at baseline. Mean on-treatment nadir total T concentrations were 13, 83, 106, 122, and 250 ng/dL in the placebo, 3-, 6.25-, 12.5-, and 25-mg groups, respectively. Analyses of acoustic voice parameters revealed significant lowering of average pitch in the 12.5- and 25-mg dose groups compared to placebo (P < .05); these changes in pitch were significantly related to increases in T concentrations. No significant dose- or concentration-dependent changes in self-reported voice handicap index scores were observed.

CONCLUSION

Testosterone administration in women with low T levels over 24 weeks was associated with dose- and concentration-dependent decreases in average pitch in the higher dose groups. These changes were seen despite the lack of self-reported changes in voice.

Association of sex hormones with sexual function, vitality, and physical function of symptomatic older men with low testosterone levels at baseline in the testosterone trials

CONTEXT

The prevalence of sexual dysfunction, low vitality, and poor physical function increases with aging, as does the prevalence of low total and free testosterone (TT and FT) levels. However, the relationship between sex hormones and age-related alterations in older men is not clear.

OBJECTIVE

To test the hypotheses that baseline serum TT, FT, estradiol (E2), and sex hormone-binding globulin (SHBG) levels are independently associated with sexual function, vitality, and physical function in older symptomatic men with low testosterone levels participating in the Testosterone Trials (TTrials).

DESIGN

Cross-sectional study of baseline measures in the TTrials.

SETTING

The study was conducted at 12 sites in the United States.

PARTICIPANTS

The 788 TTrials participants were ≥ 65 years and had evidence of sexual dysfunction, diminished vitality, and/or mobility disability, and an average of two TT < 275 ng/dL.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Question 4 of Psychosocial Daily Questionnaire (PDQ-Q4), the FACIT-Fatigue Scale, and the 6-minute walk test.

RESULTS

Baseline serum TT and FT, but not E2 or SHBG levels had small, but statistically significant associations with validated measures of sexual desire, erectile function, and sexual activity. None of these hormones was significantly associated within or across trials with FACIT-Fatigue, PHQ-9 Depression or Physical Function-10 scores, or gait speed.

CONCLUSIONS

FT and TT levels were consistently, independently, and positively associated, albeit to a small degree, with measures of sexual desire, erectile function, and sexual activity, but not with measures of vitality or physical function in symptomatic older men with low T who qualified for the TTrials.

Testosterone dose-response relationships in hysterectomized women with or without oophorectomy: effects on sexual function, body composition, muscle performance and physical function in a randomized trial

OBJECTIVE

This study aims to determine the dose-dependent effects of testosterone on sexual function, body composition, muscle performance, and physical function in hysterectomized women with or without oophorectomy.

METHODS

Seventy-one postmenopausal women who previously underwent hysterectomy with or without oophorectomy and had total testosterone levels less than 31 ng/dL or free testosterone levels less than 3.5 pg/mL received a standardized transdermal estradiol regimen during the 12-week run-in period and were randomized to receive weekly intramuscular injections of placebo or 3, 6.25, 12.5, or 25 mg of testosterone enanthate for 24 weeks. Total and free testosterone levels were measured by liquid chromatography-tandem mass spectrometry and equilibrium dialysis, respectively. The primary outcome was change in sexual function measured by the Brief Index of Sexual Functioning for Women. Secondary outcomes included changes in sexual activity, sexual distress, Derogatis Interview for Sexual Functioning, lean body mass, fat mass, muscle strength and power, and physical function.

RESULTS

Seventy-one women were randomized; five groups were similar at baseline. Sixty-two women with analyzable data for the primary outcome were included in the final analysis. The mean on-treatment total testosterone concentrations were 19, 78, 102, 128, and 210 ng/dL in the placebo, 3-mg, 6.25-mg, 12.5-mg, and 25-mg groups, respectively. Changes in composite Brief Index of Sexual Functioning for Women scores, thoughts/desire, arousal, frequency of sexual activity, lean body mass, chest-press power, and loaded stair-climb power were significantly related to increases in free testosterone concentrations; compared with placebo, changes were significantly greater in women assigned to the 25-mg group, but not in women in the lower-dose groups. Sexual activity increased by 2.7 encounters per week in the 25-mg group. The frequency of androgenic adverse events was low.

CONCLUSIONS

Testosterone administration in hysterectomized women with or without oophorectomy for 24 weeks was associated with dose and concentration-dependent gains in several domains of sexual function, lean body mass, chest-press power, and loaded stair-climb power. Long-term trials are needed to weigh improvements in these outcomes against potential long-term adverse effects.

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.

Challenges and improvements in testosterone and estradiol testing

Assays that measure steroid hormones in patient care, public health, and research need to be both accurate and precise, as these criteria help to ensure comparability across all clinical and research applications. This review addresses major issues relevant to assay variability and describes recent activities by the US Centers for Disease Control and Prevention (CDC) to improve assay performance. Currently, high degrees of accuracy and precision are not always met for testosterone and estradiol measurements; although technologies for steroid hormone measurement have advanced significantly, measurement variability within and across laboratories has not improved accordingly. Differences in calibration and specificity are discussed as sources of variability in measurement accuracy. Ultimately, a combination of factors appears to cause inaccuracy of steroid hormone measurements, with nonuniform assay calibration and lack of specificity being two major contributors to assay variability. Within-assay variability for current assays is generally high, especially at low analyte concentrations. The CDC Hormone Standardization (HoSt) Program is improving clinical assays, as evidenced by a 50% decline in mean absolute bias between mass spectrometry assays and the CDC reference method from 2007 to 2011. This program provides the measurement traceability to CDC reference methods and helps to minimize factors affecting measurement variability.

Relationships among musical aptitude, digit ratio and testosterone in men and women

Circulating adult testosterone levels, digit ratio (length of the second finger relative to the fourth finger), and directional asymmetry in digit ratio are considered sexually dimorphic traits in humans. These have been related to spatial abilities in men and women, and because similar brain structures appear to be involved in both spatial and musical abilities, neuroendocrine function may be related to musical as well as spatial cognition. To evaluate relationships among testosterone and musical ability in men and women, saliva samples were collected, testosterone concentrations assessed, and digit ratios calculated using standardized protocols in a sample of university students (N = 61), including both music and non-music majors. Results of Spearman correlations suggest that digit ratio and testosterone levels are statistically related to musical aptitude and performance only within the female sample: A) those females with greater self-reported history of exposure to music (p = 0.016) and instrument proficiency (p = 0.040) scored higher on the Advanced Measures of Music Audiation test, B) those females with higher left hand digit ratio (and perhaps lower fetal testosterone levels) were more highly ranked (p = 0.007) in the orchestra, C) female music students exhibited a trend (p = 0.082) towards higher testosterone levels compared to female non-music students, and D) female music students with higher rank in the orchestra/band had higher testosterone levels (p = 0.003) than lower ranked students. None of these relationships were significant in the male sample, although a lack of statistical power may be one cause. The effects of testosterone are likely a small part of a poorly understood system of biological and environmental stimuli that contribute to musical aptitude. Hormones may play some role in modulating the phenotype of musical ability, and this may be the case for females more so than males.

Testosterone enhances tubuloglomerular feedback by increasing superoxide production in the macula densa

Males have higher prevalence of hypertension and renal injury than females, which may be attributed in part to androgen-mediated effects on renal hemodynamics. Tubuloglomerular feedback (TGF) is an important mechanism in control of renal microcirculation. The present study examines the role of testosterone in the regulation of TGF responses. TGF was measured by micropuncture (change of stop-flow pressure, ΔPsf) in castrated Sprague-Dawley rats. The addition of testosterone (10(-7) mol/l) into the lumen increased the ΔPsf from 10.1 ± 1.2 to 12.2 ± 1.2 mmHg. To determine whether androgen receptors (AR) are involved, mRNA of AR was measured in the macula dense cells isolated by laser capture microdissection from kidneys, and a macula densa-like cell line (MMDD1). AR mRNA was expressed in the macula densa of rats and in MMDD1 cells. We next examined the effects of the AR blocker, flutamide (10(-5) mol/l) on the TGF response. The addition of flutamide blocked the effects of testosterone on TGF. The addition of Tempol (10(-4) mol/l) or polyethylene glycol-superoxide dismutase (100 U/ml) to scavenge superoxide blocked the effect of testosterone to augment TGF. We then applied apocynin to inhibit NAD(P)H oxidase and oxypurinol to inhibit xanthine oxidase and found the testosterone-induced augmentation of TGF was blocked. In additional experiments in MMDD1 cells, we found that testosterone increased O2(-) generation. Apocynin or oxypurinol blocked the testosterone-induced increases of O2(-), while blockade of COX-2 with NS-398 had no effect. These findings suggest that testosterone enhances TGF response by stimulating O2(-) production in macula densa via an AR-dependent pathway.

Genetic determinants of serum testosterone concentrations in men

Testosterone concentrations in men are associated with cardiovascular morbidity, osteoporosis, and mortality and are affected by age, smoking, and obesity. Because of serum testosterone's high heritability, we performed a meta-analysis of genome-wide association data in 8,938 men from seven cohorts and followed up the genome-wide significant findings in one in silico (n = 871) and two de novo replication cohorts (n = 4,620) to identify genetic loci significantly associated with serum testosterone concentration in men. All these loci were also associated with low serum testosterone concentration defined as <300 ng/dl. Two single-nucleotide polymorphisms at the sex hormone-binding globulin (SHBG) locus (17p13-p12) were identified as independently associated with serum testosterone concentration (rs12150660, p = 1.2×10(-41) and rs6258, p = 2.3×10(-22)). Subjects with ≥ 3 risk alleles of these variants had 6.5-fold higher risk of having low serum testosterone than subjects with no risk allele. The rs5934505 polymorphism near FAM9B on the X chromosome was also associated with testosterone concentrations (p = 5.6×10(-16)). The rs6258 polymorphism in exon 4 of SHBG affected SHBG's affinity for binding testosterone and the measured free testosterone fraction (p<0.01). Genetic variants in the SHBG locus and on the X chromosome are associated with a substantial variation in testosterone concentrations and increased risk of low testosterone. rs6258 is the first reported SHBG polymorphism, which affects testosterone binding to SHBG and the free testosterone fraction and could therefore influence the calculation of free testosterone using law-of-mass-action equation.

Human immunodeficiency virus/acquired immunodeficiency syndrome and infertility: emerging problems in the era of highly active antiretrovirals

OBJECTIVE

To review the effects of human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) in terms of its associated comorbid conditions and the side effects of antiretroviral treatment on fertility.

DESIGN

PubMed computer search to identify relevant articles.

SETTING

Research institution.

PATIENT(S)

None.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

None.

RESULT(S)

Biological alterations in reproductive physiology may account for subfertility in patients infected with HIV. Psychosocial factors in patients with HIV infection may affect their reproductive desires and outcomes. Antiretroviral medications may have direct toxicity on gametes and embryos. Available evidence indicates that fertility treatments can be a safe option for couples with HIV-discordant infection status, although the potential risk of viral transmission cannot be completely eliminated.

CONCLUSION(S)

Because their potential reproductive desires are increasingly becoming a concern in the health care of young HIV-infected patients, additional data are needed to address the effect of HIV and its treatments on their fertility and reproductive outcomes.

Higher serum free testosterone concentration in older women is associated with greater bone mineral density, lean body mass, and total fat mass: the cardiovascular health study

CONTEXT

The physiological importance of endogenous testosterone (T) in older women is poorly understood.

OBJECTIVE

The aim of the study was to determine the association of higher total and free T levels with bone mineral density (BMD), lean body mass, and fat mass in elderly women.

DESIGN

Total and free T were measured using sensitive assays in 232 community-dwelling women aged 67-94 yr who were enrolled in the Cardiovascular Health Study and had dual-energy x-ray absorptiometry scans. Cross-sectional analyses were performed to examine associations between total and free T and BMD and body composition.

RESULTS

In adjusted models, total T was directly associated with BMD at the lumbar spine (P = 0.04) and hip (P = 0.001), but not body composition outcomes, in all women, and after excluding estrogen users and adjusting for estradiol (P = 0.04 and 0.01, respectively). Free T was positively related to hip BMD, lean body mass, and body fat (all P < 0.05), with more than 10% differences in each outcome between women at the highest and lowest ends of the free T range, with attenuation after excluding estrogen users and adjusting for estradiol.

CONCLUSIONS

In the setting of the low estradiol levels found in older women, circulating T levels were associated with bone density. Women with higher free T levels had greater lean body mass, consistent with the anabolic effect of T, and, in contrast to men, greater fat mass. Mechanistic studies are required to determine whether a causal relationship exists between T, bone, and body composition in this population and the degree to which any T effects are estrogen-independent.

Reexamination of testosterone, dihydrotestosterone, estradiol and estrone levels across the menstrual cycle and in postmenopausal women measured by liquid chromatography-tandem mass spectrometry

Measuring serum androgen levels in women has been challenging due to limitations in method accuracy, precision sensitivity and specificity at low hormone levels. The clinical significance of changes in sex steroids across the menstrual cycle and lifespan has remained controversial, in part due to these limitations. We used validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays to determine testosterone (T) and dihydrotestosterone (DHT) along with estradiol (E2) and estrone (E1) levels across the menstrual cycle of 31 healthy premenopausal females and in 19 postmenopausal females. Samples were obtained in ovulatory women in the early follicular phase (EFP), midcycle and mid luteal phase (MLP). Overall, the levels of T, DHT, E2 and E1 in premenopausal women measured by LC-MS/MS were lower overall than previously reported with immunoassays. In premenopausal women, serum T, free T, E2, E1 and SHBG levels peaked at midcycle and remained higher in the MLP, whereas DHT did not change. In postmenopausal women, T, free T, SHBG and DHT were significantly lower than in premenopausal women, concomitant with declines in E2 and E1. These data support the hypothesis that the changes in T and DHT that occur across the cycle may reflect changes in SHBG and estrogen, whereas in menopause, androgen levels decrease. LC-MS/MS may provide more accurate and precise measurement of sex steroid hormones than prior immunoassay methods and can be useful to assess the clinical significance of changes in T, DHT, E2 and E1 levels in females.

Testosterone threshold levels and lean tissue mass targets needed to enhance skeletal muscle strength and function: the HORMA trial

BACKGROUND

In the HORMA (Hormonal Regulators of Muscle and Metabolism in Aging) Trial, supplemental testosterone and recombinant human growth hormone (rhGH) enhanced lean body mass, appendicular skeletal muscle mass, muscle performance, and physical function, but there was substantial interindividual variability in outcomes.

METHODS

One hundred and twelve men aged 65-90 years received testosterone gel (5 g/d vs 10 g/d via Leydig cell clamp) and rhGH (0 vs 3 vs 5 μg/kg/d) in a double-masked 2 × 3 factorial design for 16 weeks. Outcomes included lean tissue mass by dual energy x-ray absorptiometry, one-repetition maximum strength, Margaria stair power, and activity questionnaires. We used pathway analysis to determine the relationship between changes in hormone levels, muscle mass, strength, and function.

RESULTS

Increases in total testosterone of 1046 ng/dL (95% confidence interval = 1040-1051) and 898 ng/dL (95% confidence interval = 892-904) were necessary to achieve median increases in lean body mass of 1.5 kg and appendicular skeletal muscle mass of 0.8 kg, respectively, which were required to significantly enhance one-repetition maximum strength (≥ 30%). Co-treatment with rhGH lowered the testosterone levels (quantified using liquid chromatography-tandem mass spectrometry) necessary to reach these lean mass thresholds. Changes in one-repetition maximum strength were associated with increases in stair climbing power (r = .26, p = .01). Pathway analysis supported the model that changes in testosterone and insulin-like growth factor 1 levels are related to changes in lean body mass needed to enhance muscle performance and physical function. Testosterone's effects on physical activity were mediated through a different pathway because testosterone directly affected Physical Activity Score of the Elderly.

CONCLUSIONS

To enhance muscle strength and physical function, threshold improvements in lean body mass and appendicular skeletal muscle mass are necessary and these can be achieved by targeting changes in testosterone levels. rhGH augments the effects of testosterone. To maximize functional improvements, the doses of anabolic hormones should be titrated to achieve target blood levels.

Effects of testosterone administration on nocturnal cortisol secretion in healthy older men

In animal studies, testosterone decreases, whereas estrogen increases, cortisol production. In one clinical study, short-term testosterone replacement attenuated corticotrophin-releasing hormone-stimulated cortisol secretion during leuprolide-induced hypogonadism in young men. The effects of longer term testosterone treatment on spontaneous cortisol secretion in younger or older men are unknown. In a randomized, double-masked placebo-controlled study, we assessed the effects of testosterone supplementation (100 mg intramuscular every 2 week) for 26 weeks on nocturnal cortisol secretory dynamics in healthy older men. Testosterone administration increased early morning serum concentrations of free testosterone by 34%, decreased sex hormone-binding globulin by 20%, and did not alter early morning concentrations of cortisol-binding globulin or cortisol compared with placebo treatment. Testosterone did not significantly alter nocturnal mean and integrated cortisol concentrations, cortisol burst frequency, mass/burst, basal secretion, pulsatile cortisol production rate, pattern regularity, or approximate entropy. We conclude that low-dose testosterone supplementation for 26 weeks does not affect spontaneous nocturnal cortisol secretion in healthy older men.

Mothers have lower testosterone than non-mothers: evidence from the Philippines

Testosterone (T) is lower among fathers and men in committed relationships, suggesting that the hormone mediates the trade-off between mating and parenting effort. The function of T in women and responses of the hormone to relationships or motherhood are less well understood. Here we report relationships between T and pairbonding and motherhood in a random sample of 67 women (20.9 to 22.4 years old) participating in a population-based birth cohort study in the Philippines. Testosterone was measured in saliva collected at bedtime and at waking the following morning to capture circadian dynamics. Compared to non-mothers and non-pairbonded women, mothers and pairbonded women had 32% (p<0.0001) and 23% (p<0.004) lower waking T, respectively, but similar evening T. The lower waking T in mothers largely reflected reduced T in mothers of young offspring (<2 years), with mothers of older offspring (2+ years) having intermediate T. These differences were independent of measures of breastfeeding, contraceptive pill use, menstrual cycle, sleep quality, education, employment, and socioeconomic status. Our findings highlight a similar relationship between parenting and committed relationships and T in women as documented in men and suggest that caregiving of dependent young may modulate female T. Future research should clarify whether this cross-sectional association reflects a suppressive effect of motherhood on T, whether these relationships vary across cultures, and the role of T within the endocrine architecture regulating female reproductive and caregiving strategies.

Higher serum testosterone concentration in older women is associated with insulin resistance, metabolic syndrome, and cardiovascular disease

CONTEXT

Early postmenopausal women with higher testosterone (T) levels have increased insulin resistance (IR) and cardiovascular risk factors, but whether this translates into increased cardiovascular disease later in life is unknown.

OBJECTIVE

The objective of the study was to determine whether higher T levels are associated with IR, the metabolic syndrome (MetSyn), and coronary heart disease (CHD) in elderly women.

DESIGN

Total T and free T by equilibrium dialysis were measured using ultrasensitive assays in 344 women aged 65-98 yr enrolled in the Cardiovascular Health Study. Cross-sectional analyses were performed to examine the associations between total and free T and IR, MetSyn, and CHD.

RESULTS

There was a stepwise increase in the homeostasis model assessment of insulin resistance with increasing total (P = 0.0.003) and free T (P = 0.02) level and a corresponding decrease in Quantitative Insulin Sensitivity Check Index (P < 0.001 and P = 0.002, respectively). In adjusted models, higher levels of both total and free T were strongly associated with abdominal obesity and high fasting glucose, the two MetSyn components most strongly linked to IR. After adjustment, women in the top quartile of total T levels had a 3-fold greater odds of MetSyn (odds ratio 3.15, 95% confidence interval 1.57-6.35) than those in the bottom quartile and a 3-fold greater odds of CHD (odds ratio 2.95, 95% confidence interval 1.2-7.3) than those in second quartile, whereas free T was not significantly associated with MetSyn or CHD.

CONCLUSIONS

Higher levels of T are associated with IR, MetSyn, and CHD in elderly women. Whether T is a marker or mediator of cardiovascular disease in this population merits further investigation.

Preferences across the menstrual cycle for masculinity and symmetry in photographs of male faces and bodies

Background

Previous studies have shown that women increase their preference for masculinity during the fertile phase of the menstrual cycle. Evidence for a similar preference shift for symmetry is equivocal. These studies have required participants to choose between subtle variations in computer-generated stimuli, and preferences for more natural stimuli have not been investigated.

Methodology/Principal Findings

Our study employed photographs of individual males to investigate women's preferences for face and body masculinity and symmetry across the menstrual cycle. We collected attractiveness ratings from 25 normally cycling women at high- and low-fertility days of the menstrual cycle. Attractiveness ratings made by these women were correlated with independent ratings of masculinity and symmetry provided by different sets of raters. We found no evidence for any cyclic shift in female preferences. Correlations between attractiveness and masculinity, and attractiveness and symmetry did not differ significantly between high- and low-fertility test sessions. Furthermore, there was no significant difference between high- and low-fertility ratings of attractiveness.

Conclusions

These results suggest that a menstrual cycle shift in visual preferences for masculinity and symmetry may be too subtle to influence responses to real faces and bodies, and subsequent mate-choice decisions.

Gynecologic issues in the HIV-infected woman

In this article, gynecologic conditions of increased importance in the HIV-infected woman are discussed. Women living with HIV may have an increase in menstrual disorders, lower genital tract neoplasias, gynecologic surgery, and sexually transmitted infections. The literature relevant to choosing a method of contraception for HIV-positive women is also discussed. With the advent of HAART, seropositive women are now facing issues around longevity, such as menopause and disorders of bone mineral density, as well as those associated with fertility.

Testosterone and bioavailable testosterone help to distinguish between mild Cushing's syndrome and polycystic ovarian syndrome

Women with Cushing's syndrome (CS) and polycystic ovarian syndrome (PCOS) may present with similar symptoms. Subjects with mild CS lack clinical stigmata of classical CS and often have normal laboratory tests measuring hypercortisolism. Thus, distinguishing mild CS from PCOS may be difficult. We hypothesized that either total testosterone (TT) or bioavailable testosterone (BT) levels or the calculation of the free androgen index (FAI) would be low in patients with mild CS and elevated in patients with PCOS, and could help differentiate the two conditions. TT, BT, and FAI were measured in a group of 20 patients of reproductive age with mild CS and 20 PCOS patients matched for age and BMI. We used receiver operator characteristic (ROC) curves to assess the sensitivity and specificity of these measurements for the diagnosis of CS. TT (p<0.0001), BT (p=0.02), and FAI (p=0.003) were significantly elevated in PCOS patients compared to mild CS patients. Sex hormone-binding globulin was similar in both groups. The optimal cut-point for TT was 1.39 nmol/L, yielding a sensitivity of 95% and a specificity of 70%. The cut-point for BT was 0.24 nmol/L, resulting in a sensitivity of 75% and a specificity of 80%. The cut-point for FAI was 5.7, with a sensitivity of 88% and a specificity of 60%. We conclude that TT levels may be useful to discriminate between mild CS and PCOS. In patients with signs and symptoms consistent with CS and PCOS, a TT level of <1.39 nmol/L warrants a workup for CS.

Changes over 14 years in androgenicity and body mass index in a biracial cohort of reproductive-age women

BACKGROUND

Body mass index (BMI) is directly related to testosterone (total T and free T) and inversely to SHBG cross-sectionally, but little is known about how changes in body fat and androgen markers affect each other over time.

METHODS

Participants included 969 White and Black women from the Coronary Artery Risk Development in Young Adults (CARDIA) cohort, who were ages 18-30 at entry into the study and were pre- or perimenopausal 16 yr later at the time of the CARDIA Women's Study (CWS). Total T and SHBG were assayed from specimens drawn at the CWS examination and stored serum from the yr 2 and 10 CARDIA exams. Free T was calculated based on total T and SHBG. BMI and waist circumference were measured at yr 2, 10, and 16.

RESULTS

Despite clinically significant increases in BMI and waist circumference, total T and free T tended to decline, whereas SHBG remained relatively constant. BMI and waist circumference were directly correlated with free T and inversely correlated with SHBG in cross-sectional analyses. In longitudinal, multivariable analyses, an annualized increase in BMI was inversely related to a concurrent annualized decrease in SHBG (beta = -0.79 ng/dl, and se = 0.22 in Blacks; beta = -1.07 ng/dl; and se = 0.31 in Whites). However, early increases in BMI were not related to later decreases in SHBG.

CONCLUSION

Increases in adiposity are closely tied to decreases in SHBG, but changes in BMI and SHBG may occur concurrently rather than sequentially.

Effects of graded doses of testosterone on erythropoiesis in healthy young and older men

CONTEXT

Erythrocytosis is a dose-limiting adverse effect of testosterone therapy, especially in older men.

OBJECTIVE

Our objective was to compare the dose-related changes in hemoglobin and hematocrit in young and older men and determine whether age-related differences in erythropoietic response to testosterone can be explained by changes in erythropoietin and soluble transferrin receptor (sTfR) levels.

DESIGN

We conducted a secondary analysis of data from a testosterone dose-response study in young and older men who received long-acting GnRH agonist monthly plus one of five weekly doses of testosterone enanthate (25, 50, 125, 300, or 600 mg im) for 20 wk.

SETTING

The study took place at a General Clinical Research Center.

PARTICIPANTS

Participants included 60 older men aged 60-75 yr and 61 young men aged 19-35 yr.

OUTCOME MEASURES

Outcome measures included hematocrit and hemoglobin and serum erythropoietin and sTfR levels.

RESULTS

Hemoglobin and hematocrit increased significantly in a linear, dose-dependent fashion in both young and older men in response to graded doses of testosterone (P<0.0001). The increases in hemoglobin and hematocrit were significantly greater in older than young men. There was no significant difference in percent change from baseline in erythropoietin or sTfR levels across groups in either young or older men. Changes in erythropoietin or sTfR levels were not significantly correlated with changes in total or free testosterone levels.

CONCLUSIONS

Testosterone has a dose-dependent stimulatory effect on erythropoiesis in men that is more pronounced in older men. The testosterone-induced rise in hemoglobin and hematocrit and age-related differences in response to testosterone therapy may be mediated by factors other than erythropoietin and sTfR.

Long-term testosterone supplementation augments overnight growth hormone secretion in healthy older men

Circulating testosterone (T) and GH/IGF-I are diminished in healthy aging men. Short-term administration of high doses of T augments GH secretion in older men. However, effects of long-term, low-dose T supplementation on GH secretion are unknown. Our objective was to evaluate effects of long-term, low-dose T administration on nocturnal GH secretory dynamics and AM concentrations of IGF-I and IGFBP-3 in healthy older men (65-88 yr, n = 34) with low-normal T and IGF-I. In a double-masked, placebo-controlled, randomized study we assessed effects of low-dose T supplementation (100 mg im every 2 wk) for 26 wk on nocturnal GH secretory dynamics [8 PM to 8 AM, Q(20) min sampling, analyzed by multiparameter deconvolution and approximate entropy (ApEn) algorithms]. The results were that T administration increased serum total T by 33% (P = 0.004) and E(2) by 31% (P = 0.009) and decreased SHBG by 17% (P = 0.002) vs. placebo. T supplementation increased nocturnal integrated GH concentrations by 60% (P = 0.02) and pulsatile GH secretion by 79% (P = 0.05), primarily due to a twofold increase in GH secretory burst mass (P = 0.02) and a 1.9-fold increase in basal GH secretion rate (P = 0.05) vs. placebo. There were no significant changes in GH burst frequency or orderliness of GH release (ApEn). IGF-I levels increased by 22% (P = 0.02), with no significant change in IGFBP-3 levels after T vs. placebo. We conclude that low-dose T supplementation for 26 wk increases spontaneous nocturnal GH secretion and morning serum IGF-I concentrations in healthy older men.

Hormonal regulators of muscle and metabolism in aging (HORMA): design and conduct of a complex, double masked multicenter trial

BACKGROUND

Older persons often lose muscle mass, strength, and physical function. This report describes the challenges of conducting a complex clinical investigation assessing the effects of anabolic hormones on body composition, physical function, and metabolism during aging.

METHODS

HORMA is a multicenter, randomized double masked study of 65-90-year-old community dwelling men with testosterone levels of 150-550 ng/dL and IGF-1 < 167 ng/dL. Subjects were randomized to transdermal testosterone (5 or 10 g/day) and rhGH (0, 3, or 5 microg/kg/day) for 16 weeks. Outcome measures included body composition by DEXA, MRI, and (2)H(2)O dilution; muscle performance (strength, power, and fatigability), VO2peak, measures of physical function, synthesis/breakdown of myofibrillar proteins, other measures of metabolism, and quality of life.

RESULTS

Major challenges included delay in startup caused by need for 7 institutional contracts, creating a 142-page manual of operations, orientation and training, creating a 121-page CRF; enrollment inefficiencies; scheduling 16 evaluations/ subject; overnight admissions for invasive procedures and isotope infusions; large data and image management and transfer; quality control at multiples sites; staff turnover; and replacement of a clinical testing site. Impediments were largely solved by implementation of a web-based data entry and eligibility verification; electronic scheduling for multiple study visits; availability of research team members to educate and reassure subjects; more frequent site visits to validate all source documents and reliability of data entry; and intensifying quality control in testing and imaging. The study exceeded the target goal of 108 (n = 112) completely evaluable cases. Two interim DSMB meetings confirmed the lack of excessive adverse events, lack of center effects, comparability of subjects, and that distribution of subjects and enrollment will not jeopardize outcomes or generalizability of results.

CONCLUSIONS

Flexibility and rapidly solving evolving problems is critical when conducting highly complex multicenter metabolic studies.

Dehydroepiandrosterone secretion in healthy older men and women: effects of testosterone and growth hormone administration in older men

CONTEXT

Aging is associated with diminished gonadal steroid and GH/IGF-I axis activity; whether these changes contribute to the parallel declines of dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS) production is unknown, as are the effects of sex steroid and/or GH administration on DHEA and DHEAS production.

OBJECTIVE

Our objective was to evaluate morning DHEAS concentrations and nocturnal DHEA secretory dynamics in healthy older men and women, before and after chronic administration of sex steroid(s) alone, GH alone, sex steroid(s) combined with GH, or placebo alone.

DESIGN

We compared nocturnal DHEA secretory dynamics (2000 h to 0800 h, sampling every 20 min, analyzed by multiparameter deconvolution and approximate entropy algorithms) in healthy older (65-88 yr) men (n = 68) and women (n = 36), both before and after 26 wk of administration of sex steroid(s) alone [testosterone (T) in men or estrogen/progesterone in women], GH alone, sex steroid(s) combined with GH, or placebo alone.

RESULTS

Morning concentrations of DHEAS were lower; nocturnal DHEA pulsatile production rate, burst frequency, and amplitude were higher; and half-life was shorter in women (P < 0.05). Nocturnal integrated DHEA concentrations, total production rate, and approximate entropy did not differ significantly by sex. Because of small treatment group sizes in women, only hormone intervention results in men are presented. In men, T and T plus GH administration significantly decreased nocturnal integrated DHEA but not morning DHEAS concentrations. GH alone exerted no significant effects on nocturnal DHEA secretion or morning DHEAS.

CONCLUSIONS

Spontaneous nocturnal DHEA secretion is sexually dimorphic in healthy older individuals, and T administration decreases nocturnal DHEA secretion in older men. The clinical significance of sex steroid modulation of DHEA secretion in older persons remains to be elucidated.

Effect of testosterone on the female anterior cruciate ligament

Injuries to the anterior cruciate ligament (ACL) result in immediate and long-term morbidity and expense. Young women are more likely to sustain ACL injuries than men who participate in similar athletic and military activities. Although significant attention has focused on the role that female sex hormones may play in this disparity, it is still unclear whether the female ACL also responds to androgens. The purpose of this study was to determine whether the female ACL was an androgen-responsive tissue. To identify and localize androgen receptors in the female ACL, we used Western blotting and immunofluorescent labeling, respectively, of ACL tissue harvested during surgery from young women (n = 3). We then measured ACL stiffness and assessed total testosterone (T) and free [free androgen index (FAI)] testosterone concentrations, as well as relative estradiol to testosterone ratios (E(2)/T and E(2)/FAI) at three consecutive menstrual stages (n = 20). There were significant rank-order correlations between T (0.48, P = 0.031), FAI (0.44, P = 0.053), E(2)/T (-0.71, P < 0.001), E(2)/FAI (-0.63, P = 0.003), and ACL stiffness near ovulation. With the influences of the other variables controlled, there were significant negative partial rank-order correlations between ACL stiffness and E(2)/T (-0.72, P < 0.001) and E(2)/FAI (-0.59, P = 0.012). The partial order residuals for T and FAI were not significant. These findings suggest that the female ACL is an androgen-responsive tissue but that T and FAI are not independent predictors of ACL stiffness near ovulation. Instead, the relationship between T, FAI, and ACL stiffness was likely influenced by another hormone or sex hormone binding globulin.

Testosterone replacement and resistance exercise in HIV-infected men with weight loss and low testosterone levels

CONTEXT

Previous studies of testosterone supplementation in HIV-infected men failed to demonstrate improvement in muscle strength. The effects of resistance exercise combined with testosterone supplementation in HIV-infected men are unknown.

OBJECTIVE

To determine the effects of testosterone replacement with and without resistance exercise on muscle strength and body composition in HIV-infected men with low testosterone levels and weight loss.

DESIGN AND SETTING

Placebo-controlled, double-blind, randomized clinical trial conducted from September 1995 to July 1998 at a general clinical research center.

PARTICIPANTS

Sixty-one HIV-infected men aged 18 to 50 years with serum testosterone levels of less than 12.1 nmol/L (349 ng/dL) and weight loss of 5% or more in the previous 6 months, 49 of whom completed the study.

INTERVENTIONS

Participants were randomly assigned to 1 of 4 groups: placebo, no exercise (n = 14); testosterone enanthate (100 mg/wk intramuscularly), no exercise (n = 17); placebo and exercise (n = 15); or testosterone and exercise (n = 15). Treatment duration was 16 weeks.

MAIN OUTCOME MEASURES

Changes in muscle strength, body weight, thigh muscle volume, and lean body mass compared among the 4 treatment groups.

RESULTS

Body weight increased significantly by 2.6 kg (P<.001) in men receiving testosterone alone and by 2.2 kg (P = .02) in men who exercised alone but did not change in men receiving placebo alone (-0.5 kg; P = .55) or testosterone and exercise (0.7 kg; P = .08). Men treated with testosterone alone, exercise alone, or both experienced significant increases in maximum voluntary muscle strength in leg press (range, 22%-30%), leg curls (range, 18%-36%), bench press (range, 19%-33%), and latissimus pulls (range, 17%-33%). Gains in strength in all exercise categories were greater in men assigned to the testosterone-exercise group or to the exercise-alone group than in those assigned to the placebo-alone group. There was a greater increase in thigh muscle volume in men receiving testosterone alone (mean change, 40 cm3; P<.001 vs zero change) or exercise alone (62 cm3; P = .003) than in men receiving placebo alone (5 cm3; P = .70). Average lean body mass increased by 2.3 kg (P = .004) and 2.6 kg (P<.001), respectively, in men who received testosterone alone or testosterone and exercise but did not change in men receiving placebo alone (0.9 kg; P = .21). Hemoglobin levels increased in men receiving testosterone but not in those receiving placebo.

CONCLUSION

Our data suggest that testosterone and resistance exercise promote gains in body weight, muscle mass, muscle strength, and lean body mass in HIV-infected men with weight loss and low testosterone levels. Testosterone and exercise together did not produce greater gains than either intervention alone.

Organization of the human myostatin gene and expression in healthy men and HIV-infected men with muscle wasting

Myostatin, a member of the transforming growth factor-beta superfamily, is a genetic determinant of skeletal muscle growth. Mice and cattle with inactivating mutations of myostatin have marked muscle hypertrophy. However, it is not known whether myostatin regulates skeletal muscle growth in adult men and whether increased myostatin expression contributes to wasting in chronic illness. We examined the hypothesis that myostatin expression correlates inversely with fat-free mass in humans and that increased expression of the myostatin gene is associated with weight loss in men with AIDS wasting syndrome. We therefore cloned the human myostatin gene and cDNA and examined the gene's expression in the skeletal muscle and serum of healthy and HIV-infected men. The myostatin gene comprises three exons and two introns, maps to chromosomal region 2q33.2, has three putative transcription initiation sites, and is transcribed as a 3.1-kb mRNA species that encodes a 375-aa precursor protein. Myostatin is expressed uniquely in the human skeletal muscle as a 26-kDa mature glycoprotein (myostatin-immunoreactive protein) and secreted into the plasma. Myostatin immunoreactivity is detectable in human skeletal muscle in both type 1 and 2 fibers. The serum and intramuscular concentrations of myostatin-immunoreactive protein are increased in HIV-infected men with weight loss compared with healthy men and correlate inversely with fat-free mass index. These data support the hypothesis that myostatin is an attenuator of skeletal muscle growth in adult men and contributes to muscle wasting in HIV-infected men.