Testosterone dose-response relationships in healthy young men

Androgen Misuse and Abuse

Androgens are potent drugs requiring prescription for valid medical indications but are misused for invalid, unproven, or off-label reasons as well as being abused without prescription for illicit nonmedical application for performance or image enhancement. Following discovery and first clinical application of testosterone in the 1930s, commercialization of testosterone and synthetic androgens proliferated in the decades after World War II. It remains among the oldest marketed drugs in therapeutic use, yet after 8 decades of clinical use, the sole unequivocal indication for testosterone remains in replacement therapy for pathological hypogonadism, organic disorders of the male reproductive system. Nevertheless, wider claims assert unproven, unsafe, or implausible benefits for testosterone, mostly representing wishful thinking about rejuvenation. Over recent decades, this created an epidemic of testosterone misuse involving prescription as a revitalizing tonic for anti-aging, sexual dysfunction and/or obesity, where efficacy and safety remains unproven and doubtful. Androgen abuse originated during the Cold War as an epidemic of androgen doping among elite athletes for performance enhancement before the 1980s when it crossed over into the general community to become an endemic variant of drug abuse in sufficiently affluent communities that support an illicit drug industry geared to bodybuilding and aiming to create a hypermasculine body physique and image. This review focuses on the misuse of testosterone, defined as prescribing without valid clinical indications, and abuse of testosterone or synthetic androgens (androgen abuse), defined as the illicit use of androgens without prescription or valid indications, typically by athletes, bodybuilders and others for image-oriented, cosmetic, or occupational reasons.

Effects of GnRH agonists on testosterone and testosterone-stimulated parameters for contraception and aggression reduction in male lion-tailed Macaques (Macaca silenus)

Managing social groups in zoos requires controlling reproduction in individuals that do not have a current breeding recommendation, while simultaneously maintaining social harmony and animal well-being. Contraceptives, such as gonadotropin releasing-hormone (GnRH) agonists, that suppress testosterone production, offer a potential solution. They achieve infertility by interrupting spermatogenesis and may ameliorate androgen-induced aggression. This study investigated the effects of two GnRH agonists, histrelin and deslorelin, on testosterone, testis size, body weight and sperm production in male lion-tailed macaques, along with subjective observations of aggressive behavior. Five trials at three institutions with 14 males demonstrated that 100 mg histrelin or 9 to 12 mg of deslorelin could at least temporarily reduce testosterone, but a lower 6 mg dose was ineffective. However, ability of deslorelin to produce azoospermia varied among males, even at the highest dose. In general, a higher dose was needed (1) to achieve than to maintain suppression of any measured parameter and (2) to suppress sperm production than testosterone concentration. Testosterone production was also more likely than sperm production to recover, suggesting possible damage to seminiferous tubules but not to Leydig cells. Aggressive behavior was reduced in all but the group receiving the lowest dose. This allowed social groups to be maintained for many years despite recovery of testosterone in some males, suggesting that new social roles had been learned and become independent of androgen influence.

Serum Insulin-like Factor 3 Levels Are Reduced in Former Androgen Users, Suggesting Impaired Leydig Cell Capacity

CONTEXT

Illicit use of anabolic androgenic steroids (AAS) is frequently observed in men and is associated with subsequent testosterone deficiency although the long-term effect on gonadal function is still unclear. Serum insulin-like factor 3 (INSL3) has been suggested to be a superior biomarker of Leydig cell secretory capacity compared to testosterone.

OBJECTIVE

This study aimed to investigate serum INSL3 concentrations in AAS users.

METHODS

This community-based, cross-sectional study included men aged 18 to 50 years, involved in recreational strength training and allocated to 1 of 3 groups: never-AAS users as controls (n = 44), current (n = 46), or former AAS users (n = 42) with an average duration since AAS cessation of 32 (23 ; 45) months.

RESULTS

Serum INSL3 was lower in current AAS users and former AAS users than in controls, median (interquartile range), 0.04 µg/L (nondetectable [ND]-0.07 µg/L) and 0.39 µg/L (0.24-0.62 µg/L) vs 0.59 µg/L (0.45-0.72 µg/L), P less than .001. Former AAS users exhibited lower serum INSL3 levels than controls in a multivariable linear regression even after adjusting for serum total testosterone (TT) and other relevant confounders, (B) (95% CI), -0.16 µg/L (95% CI, -0.29 to -0.04 µg/L), P equal to .011. INSL3 and TT were not associated in the model, P equal to .821. Longer accumulated AAS duration (log2) was associated with lower serum INSL3 in former AAS users, (B) (95% CI), -0.08 (95% CI, -0.14 to -0.01), P equal to .022. Serum INSL3, but not inhibin B or testosterone, was associated with testicular size in a multivariate linear regression, (B) (95% CI); 4.7 (95% CI, 0.5 to 8.9), P equal to .030.

CONCLUSION

Serum INSL3 is reduced years following AAS cessation in men, independently of testosterone, suggesting persistently impaired Leydig cell capacity.

Erectile Dysfunction as a Cardiovascular Risk Factor: Time to Step Up?

BACKGROUND

Erectile dysfunction (ED) is a major health problem that affects a significant proportion of the general population, and its prevalence is even higher in patients with CV risk factors and/or disease. ED and cardiovascular (CV) disease share several common pathophysiological mechanisms, and thus, the potential role of ED as a predictor of CV events has emerged as a significant research aspect.

OBJECTIVE

The purpose of this review is to present and critically discuss data assessing the relation between ED and CV disease and the potential predictive value of ED for CV events.

METHODS

A comprehensive review of the literature has been performed to identify studies evaluating the association between ED and CV disease.

RESULTS

Several cross-sectional and prospective studies have examined the association between ED and CV disease and found an increased prevalence of ED in patients with CV disease. ED was shown to independently predict future CV events. Importantly, ED was found to precede the development of overt coronary artery disease (CAD) by 3 to 5 years, offering a "time window" to properly manage these patients before the clinical manifestation of CAD. Phosphodiesterase type 5 inhibitors are the first-line treatment option for ED and were shown to be safe in terms of CV events in patients with and without CV disease.

CONCLUSION

Accumulating evidence supports a strong predictive role of ED for CV events. Early identification of ED could allow for the optimal management of these patients to reduce the risk for a CV event to occur.

Can conditions of skeletal muscle loss be improved by combining exercise with anabolic-androgenic steroids? A systematic review and meta-analysis of testosterone-based interventions

Sarcopenia, cachexia, and atrophy due to inactivity and disease states are characterized by a loss of skeletal muscle mass, often accompanied by reduced levels of anabolic hormones (e.g. testosterone). These conditions are associated with an increase in mortality, hospitalization and worsening in quality of life. Both physical exercise (EX) and anabolic-androgenic steroid (AAS) administration can improve the prognosis of patients as they increase physical functionality. However, there is a gap in the literature as to the impact of these therapies on the gains in strength and muscle mass and their implications for patient safety. Accordingly, we performed a random-effects meta-analysis to elucidate the effects of AAS and/or EX interventions on lean body mass (LBM) and muscle strength in conditions involving muscle loss. A systematic search for relevant clinical trials was conducted in MEDLINE, EMBASE, SCOPUS, Web of Science, and SPORTDiscus. Comparisons included AAS vs. Control, EX vs. Control, AAS vs. EX, AAS + EX vs. AAS and AAS + EX vs. EX. A total of 1114 individuals were analyzed. AAS increased LBM (effect size [ES]: 0.46; 95% CI: 0.25, 0.68, P = 0.00) and muscle strength (ES: 0.31; 95% CI: 0.08, 0.53, P = 0.01) when compared to a control group. EX promoted an increase in muscular strength (ES: 0.89; 95% CI: 0.53, 1.25, P = 0.00), with no effect on LBM when compared to the control group (ES: 0.15; 95% CI: -0.07, 0.38, P = 0.17). AAS did not demonstrate statistically significant differences when compared to EX for LBM and muscle strength. The combination of EX + AAS promoted a greater increase in LBM and muscular strength when compared to AAS or EX in isolation. Qualitatively, AAS administration had relatively few side effects. Significant heterogeneity was found in some analyses, which may be explained by the use of different AAS types and EX protocols. Our findings suggest that AAS administration in cachectic and sarcopenic conditions may be a viable interventional strategy to enhance muscle function when exercise is not a possible approach. Moreover, combining AAS with exercise may enhance positive outcomes in this population.

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.

The effect of sex hormones on skeletal muscle adaptation in females

Sex steroids, commonly referred to as sex hormones, are integral to the development and maintenance of the human reproductive system. In addition, male (androgens) and female (estrogens and progestogens) sex hormones promote the development of secondary sex characteristics by targeting a range of other tissues, including skeletal muscle. The role of androgens on skeletal muscle mass, function and metabolism has been well described in males, yet female specific studies are scarce in the literature. This narrative review summarises the available evidence around the mechanistic role of androgens, estrogens and progestogens in female skeletal muscle. An analysis of the literature indicates that sex steroids play important roles in the regulation of female skeletal muscle mass and function. The free fractions of testosterone and progesterone in serum were consistently associated with the regulation of muscle mass, while estrogens may be primarily involved in mediating the muscle contractile function in conjunction with other sex hormones. Muscle strength was however not directly associated with any hormone in isolation when at physiological concentrations. Importantly, recent evidence suggests that intramuscular sex hormone concentrations may be more strongly associated with muscle size and function than circulating forms, providing interesting opportunities for future research. By combining cross-sectional, interventional and mechanical studies, this review aims to provide a broad, multidisciplinary picture of the current knowledge of the effects of sex steroids on skeletal muscle in females, with a focus on the regulation of muscle size and function and an insight into their clinical implications. HighlightsFree testosterone, but not total testosterone, is associated with lean mass but not strength in pre- and post-menopausal females.Progesterone and estrogens may regulate muscle mass and strength, respectively, in females.Intra-muscular steroids may be more closely associated to muscle mass and strength, compared to systemic fractions.

Testosterone Boosters Intake in Athletes: Current Evidence and Further Directions

“Testosterone boosters” (TB)—are supplements that are claimed to increase testosterone levels in the human body. While the consumption of TB may be popular among athletes, there is insufficient evidence both about the safety and the real efficacy of TB. In our review, we searched MEDLINE/PubMed and Cochrane Library for studies on the effects of 15 substances that are claimed to increase testosterone levels Anacyclus pyrethrum; Bulbine natalensis; Epimedium (horny goat weed); L-arginine; L-carnitine; magnesium; Mucuna pruriens; pantothenic acid; selenium; shilajit Eurycoma longifolia (Tongkat Ali); Serenoa repens (saw palmetto); boron; Withania somnifera (ashwagandha); and Trigonella foenum-graecum (fenugreek) in athletes and healthy adults under 55 years of age. We found such studies regarding 10 out of 15 substances: L-arginine (3 studies); L-carnitine (2); magnesium (1); selenium (2); shilajit (1); Tongkat Ali (2); Serenoa repens (1); boron (3); ashwagandha root (2); and fenugreek (7). Many of them fail to prove the efficacy of these substances to increase testosterone levels. Tongkat Ali, ashwagandha, and fenugreek were the substances with the strongest evidence. The positive effect of magnesium and shilajit on testosterone concentration was shown in single studies. Conflicting data found that L-arginine, L-carnitine, Serenoa repens, selenium and boron do not appear to increase testosterone levels. There are almost no data on the safety profile of various TB components; however, certain TB components may be linked to coagulation, and pancreatic and hepatic disorders. Based on the review, the authors conclude that at present TB cannot be recommended for use by athletes due to insufficient data on their efficacy and safety.

Sex Differences in the Oxygenation of the Left and Right Prefrontal Cortex during Moderate-Intensity Exercise

INTRODUCTION

Differences in cognitive performance with exercise between men and women have previously been reported. In this study, we evaluated between-sex differences in oxygenation of the prefrontal cortex (PFC) with moderate-intensity aerobic exercise (AE), which could contribute to noted differences in cognitive function.

METHOD

The subjects were ten men (age, 21.5 ± 0.5 years; height, 171.7 ± 4.8 cm; weight, 65.6 ± 5.6 kg) and ten women (age, 21.4 ± 0.5 years; height, 157.6 ± 4.9 cm; weight, 51.3 ± 6.5 kg). They completed our AE protocol, consisting of a 30-min leg-ergometer cycling at an intensity of 50% peak oxygen uptake, with an initial 4-min rest period for baseline measurement. Measures of the dynamics of cerebral oxygenation included: oxygenated hemoglobin (O2Hb) in the left and right PFC (LR-PFC) and deoxygenated hemoglobin (HHb). The 30-min exercise period was subdivided into six 5-min phases, with the average and peak values determined in each phase.

RESULTS

A significant interaction was found between LR-PFC HHb and sex (p < 0.001), with significantly higher values in men than in women in phases 3-6 (p < 0.05).

CONCLUSION

We report a significant sex effect of HHb in the LR-PFC.

Total testosterone is not associated with lean mass or handgrip strength in pre-menopausal females

The aim of this study was to examine the relationship between endogenous testosterone concentrations and lean mass and handgrip strength in healthy, pre-menopausal females. Testosterone has been positively associated with lean mass and strength in young and older males. Whether this relationship exists in pre-menopausal females is unknown. Secondary data from the 2013-2014 National Health and Nutrition Examination Survey were used to test this relationship. Females were aged 18-40 (n = 716, age 30 ± 6 years, mean ± SD) and pre-menopausal. Multivariate linear regression models were used to examine associations between total testosterone, lean mass index (LMI) and handgrip strength. Mean ± SD testosterone concentration was 1.0 ± 0.6 nmol L-1 and mean free androgen index (FAI) was 0.02 ± 0.02. In pre-menopausal females, testosterone was not associated with LMI (β = 0.05; 95%CI - 0.04, 0.15; p = 0.237) or handgrip strength (β = 0.01; 95%CI - 0.11, 0.12; p = 0.926) in a statistically significant manner. Conversely, FAI was associated with LMI (β = - 0.03; 95%CI - 0.05, - 0.02; p = 0.000) in a quadratic manner, meaning LMI increases with increasing FAI levels. Handgrip strength was not associated with FAI (β = 0.06; 95%CI - 0.02, 0.15; p = 0.137). These findings indicate that FAI, but not total testosterone, is associated with LMI in pre-menopausal females. Neither FAI nor total testosterone are associated with handgrip strength in pre-menopausal females when testosterone concentrations are not altered pharmacologically.

Androgen receptor gene microsatellite polymorphism is associated with muscle mass and strength in bodybuilders and power athlete status

BACKGROUND

The androgen receptor (AR) gene contains a polymorphic trinucleotide (CAG) microsatellite repeat sequence (short or long alleles) that has been associated with fat-free mass in untrained men, which needs to be replicated in athletic cohorts.

AIM

The purpose of this study was to explore the AR (CAG)_n polymorphism in trained individuals.

SUBJECTS AND METHODS

A total of 61 professional bodybuilders (40 males, 21 females), 73 elite male sprinters and weightlifters and 186 male controls were enrolled in this study. The influence of the AR (CAG)_n polymorphism on muscle mass and strength was assessed in bodybuilders, while the frequencies of AR (CAG)_n alleles were compared between power athletes and non-athletes.

RESULTS

The polymorphism was associated with anthropometric and strength measurements in bodybuilders of both genders. Those with ≥21 CAG repeats (i.e. carriers of long alleles) exhibited greater (p < 0.05) body mass index, absolute muscle mass, arm/thigh circumference and upper/lower limb strength compared to those with <21 CAG repeats. Furthermore, carriers of ≥21 CAG repeats were more frequent among power athletes compared to controls (p = 0.0076).

CONCLUSIONS

Long alleles of the AR (CAG)_n polymorphism were associated with greater muscle mass and strength in bodybuilders, and power athlete status.

Review Article: Anabolic-Androgenic Steroids, Violence, and Crime: Two Cases and Literature Review

BACKGROUND AND OBJECTIVES

Anabolic-androgenic steroid (AAS) use has become a major worldwide substance use disorder, affecting tens of millions of individuals. Importantly, it is now increasingly recognized that some individuals develop uncharacteristically violent or criminal behaviors when using AAS. We sought to summarize available information on this topic.

METHODS

We reviewed the published literature on AAS-induced behavioral effects and augmented this information with extensive observations from our clinical and forensic experience.

RESULTS

It is now generally accepted that some AAS users develop uncharacteristically violent or criminal behaviors while taking these drugs. Although these behaviors may partially reflect premorbid psychopathology, sociocultural factors, or expectational effects, accumulating evidence suggests that they are also attributable to biological effects of AAS themselves. The mechanism of these effects remains speculative, but preliminary data suggest a possible role for brain regions involved in emotional reactivity, such as the amygdala and regions involved in cognitive control, including the frontal cortex. For unknown reasons, these effects appear idiosyncratic; most AAS users display few behavioral effects, but a minority develops severe effects.

CONCLUSION AND SCIENTIFIC SIGNIFICANCE

Professionals encountering AAS users in clinical or forensic settings should be alert to the possibility of AAS-induced violence or criminality and should employ strategies to assess whether AAS is indeed a contributory factor in a given case. Further research is needed to elucidate the mechanism of AAS-induced violence and to explain why only a subset of AAS users appears vulnerable to these effects. (Am J Addict 2021;00:00-00).

An Abductive Inference Approach to Assess the Performance-Enhancing Effects of Drugs Included on the World Anti-Doping Agency Prohibited List

Some have questioned the evidence for performance-enhancing effects of several substances included on the World Anti-Doping Agency's Prohibited List due to the divergent or inconclusive findings in randomized controlled trials (RCTs). However, inductive statistical inference based on RCTs-only may result in biased conclusions because of the scarcity of studies, inter-study heterogeneity, too few outcome events, or insufficient power. An abductive inference approach, where the body of evidence is evaluated beyond considerations of statistical significance, may serve as a tool to assess the plausibility of performance-enhancing effects of substances by also considering observations and facts not solely obtained from RCTs. Herein, we explored the applicability of an abductive inference approach as a tool to assess the performance-enhancing effects of substances included on the Prohibited List. We applied an abductive inference approach to make inferences on debated issues pertaining to the ergogenic effects of recombinant human erythropoietin (rHuEPO), beta₂-agonists and anabolic androgenic steroids (AAS), and extended the approach to more controversial drug classes where RCTs are limited. We report that an abductive inference approach is a useful tool to assess the ergogenic effect of substances included on the Prohibited List-particularly for substances where inductive inference is inconclusive. Specifically, a systematic abductive inference approach can aid researchers in assessing the effects of doping substances, either by leading to suggestions of causal relationships or identifying the need for additional research.

Clinical laboratory reference values in adults in Kisumu County, Western Kenya; hematology, chemistry and CD4

BACKGROUND

Clinical laboratory reference intervals (RIs) are essential for diagnosing and managing patients in routine clinical care as well as establishing eligibility criteria and defining adverse events in clinical trials, but may vary by age, gender, genetics, nutrition and geographic location. It is, therefore, critical to establish region-specific reference values in order to inform clinical decision-making.

METHODS

We analyzed data from a prospective observational HIV incidence cohort study in Kombewa, Kenya. Study participants were healthy males and females, aged 18-35 years, without HIV. Median and 95% reference values (2.5th percentile to 97.5th percentile) were calculated for laboratory parameters including hematology, chemistry studies, and CD4 T cell count. Standard Deviation Ratios (SDR) and Bias Ratios (BR) are presented as measures of effect magnitude. Findings were compared with those from the United States and other Kenyan studies.

RESULTS

A total of 299 participants were analyzed with a median age of 24 years (interquartile range: 21-28). Ratio of males to females was 0.9:1. Hemoglobin range (2.5th-97.5th percentiles) was 12.0-17.9 g/dL and 9.5-15.3 g/dL in men and women respectively. In the cohort, MCV range was 59-95fL, WBC 3.7-9.2×103/μL, and platelet 154-401×103/μL. Chemistry values were higher in males; the creatinine RI was 59-103 μmol/L in males vs. 46-76 μmol/L in females (BRUL>.3); and the alanine transferase range was 8.8-45.3 U/L in males vs. 7.5-36.8 U/L in females (SDR>.3). The overall CD4 T cell count RI was 491-1381 cells/μL. Some parameters including hemoglobin, neutrophil, creatinine and ALT varied with that from prior studies in Kenya and the US.

CONCLUSION

This study not only provides clinical reference intervals for a population in Kisumu County but also highlights the variations in comparable settings, accentuating the requirement for region-specific reference values to improve patient care, scientific validity, and quality of clinical trials in Africa.

Disposition of Urinary and Serum Steroid Metabolites in Response to Testosterone Administration in Healthy Women

CONTEXT

Little is known about how exogenous testosterone (T) affects the steroid profile in women. More knowledge would give the antidoping community keys as to how to interpret tests and detect doping.

OBJECTIVE

This work aimed to investigate the steroid profile in serum and urine in young healthy women after T administration.

METHODS

In a randomized, double-blind, placebo-controlled study, 48 healthy young women were assigned to daily treatment with T cream (10 mg) or placebo (1:1) for 10 weeks. Urine and blood were collected before and at the end of treatment. Serum steroids were analyzed with liquid chromatography-tandem mass spectrometry, and urine levels of T, epitestosterone (E), and metabolites included in the Athlete Biological Passport (ABP) were analyzed with gas chromatography-tandem mass spectrometry.

RESULTS

In serum, T and dihydrotestosterone levels increased, whereas sex hormone-binding globulin and 17-hydroxyprogesterone decreased after T treatment as compared to placebo. In urine, T and 5α-androstanediol increased in the T group. The median T increase in serum was 5.0-fold (range, 1.2-18.2) and correlated to a 2.2-fold (range, 0.4-14.4) median increase in T/E in urine (rs = 0.76). Only 2 of the 24 women receiving T reached the T/E cutoff ratio of 4, whereas when the results were added to the ABP, 6 of 15 participants showed atypically high T/E (40%). In comparison, 22/24 women in the T group increased serum T more than 99.9% of the upper confidence interval of nontreated values.

CONCLUSION

It seems that the T/E ratio is not sufficient to detect exogenous T in women. Serum total T concentrations could serve as a complementary marker of doping.

The role of androgen therapy in prostate cancer: from testosterone replacement therapy to bipolar androgen therapy

Testosterone replacement therapy (TRT) is the primary treatment for male testosterone deficiency. This therapy raises concerns over the risk of prostate cancer (PC), because testosterone has historically been considered the fuel for PC. We discuss the re-evaluation of the relationship between androgen and PC, and highlight the safety of TRT in the treatment of symptomatic men with testosterone deficiency who have low-risk disease after treatment for localized PC with surgery or radiation. Furthermore, we review the clinical application and potential mechanisms of bipolar androgen therapy (BAT) in the treatment of castration-resistant PC, emphasizing that much remains to be done before BAT can be broadly applied.

Do Sex Differences in Physiology Confer a Female Advantage in Ultra-Endurance Sport?

Ultra-endurance has been defined as any exercise bout that exceeds 6 h. A number of exceptional, record-breaking performances by female athletes in ultra-endurance sport have roused speculation that they might be predisposed to success in such events. Indeed, while the male-to-female performance gap in traditional endurance sport (e.g., marathon) remains at ~ 10%, the disparity in ultra-endurance competition has been reported as low as 4% despite the markedly lower number of female participants. Moreover, females generally outperform males in extreme-distance swimming. The issue is complex, however, with many sports-specific considerations and caveats. This review summarizes the sex-based differences in physiological functions and draws attention to those which likely determine success in extreme exercise endeavors. The aim is to provide a balanced discussion of the female versus male predisposition to ultra-endurance sport. Herein, we discuss sex-based differences in muscle morphology and fatigability, respiratory-neuromechanical function, substrate utilization, oxygen utilization, gastrointestinal structure and function, and hormonal control. The literature indicates that while females exhibit numerous phenotypes that would be expected to confer an advantage in ultra-endurance competition (e.g., greater fatigue resistance, greater substrate efficiency, and lower energetic demands), they also exhibit several characteristics that unequivocally impinge on performance (e.g., lower O₂-carrying capacity, increased prevalence of GI distress, and sex-hormone effects on cellular function/injury risk). Crucially, the advantageous traits may only manifest as ergogenic in the extreme endurance events which, paradoxically, are those that females less often contest. The title question should be revisited in the coming years, when/if the number of female participants increases.

Doping practices in international weightlifting: analysis of sanctioned athletes/support personnel from 2008 to 2019 and retesting of samples from the 2008 and 2012 Olympic Games

BACKGROUND

The pervasiveness of doping and findings of anti-doping corruption threaten weightlifting's position at the 2024 Olympic Games. Analysing the practices of doping in weightlifters could identify patterns in doping that assist in future detection.

METHODS

We analysed publicly available data on sanctioned athletes/support personnel from the International Weightlifting Federation between 2008 and 2019 and announced retrospective Anti-Doping Rule Violations (ADRVs) from the 2008 and 2012 Olympic Games.

RESULTS

There were 565 sanctions between 2008 and 2019 of which 82% related to the detection of exogenous Anabolic Androgenic Steroid (AAS) metabolites and markers indicating endogenous AAS usage. The detection of exogenous AAS metabolites, markers of endogenous AAS usage and other substance metabolites varied by IWF Continental Federation (p ≤ 0.05) with Europe (74%, 11%, 15%) and Asia (70%, 15%, 15%) showing a higher detection of exogenous AAS compared to Pan America (37%, 30%, 33%) and Africa (50%, 17%, 33%). When looking at the 10 most detected substances, the nations with the highest number of sanctions (range 17-35) all had at least one overrepresented substance that accounted for 38-60% of all detected substances. The targeted re-analysis of samples from the 2008 and 2012 Olympic Games due to the discovery of long-term metabolites for exogenous AAS resulted in 61 weightlifters producing retrospective ADRVs. This includes 34 original medallists (9 gold, 10 silver and 15 bronze), the highest of any sport identified by Olympic Games sample re-testing. The exogenous AAS dehydrochloromethyltestosterone and stanozolol accounted for 83% of detected substances and were present in 95% of these samples.

CONCLUSION

Based on these findings of regional differences in doping practices, weightlifting would benefit from the targeted testing of certain regions and continuing investment in long-term sample storage as the sensitivity and specificity of detection continues to improve.

Masculinising testosterone treatment and effects on preclinical cardiovascular disease, muscle strength and power, aggression, physical fitness and respiratory function in transgender men: protocol for a 10-year, prospective, observational cohort study in Denmark at the Body Identity Clinic (BIC)

INTRODUCTION

The number of individuals with gender dysphoria seeking gender-affirming treatment is increasing. The short-term and long-term effects of masculinising treatment with testosterone are debated as serum testosterone increases up to 20-fold compared with cisgender women. We will investigate short-term and long-term effects of masculinising testosterone treatment on preclinical and clinical coronary disease, muscle strength and power, oxygen consumption (VO₂) max, cardiac and respiratory function and quality of life including aggression in transgender men.

METHODS AND ANALYSES

Prospective, single-centre, observational cohort study at the Body Identity Clinic (BIC), Odense University Hospital, Denmark. Investigations are performed at inclusion and following 1, 3, 5 and 10 years of testosterone therapy. Non-calcified coronary plaque volume and calcium score are estimated by coronary CT angiography. CT is only performed at inclusion and following 1 and 10 years. Upper body muscle strength and power are measured by a 'low row' weight stack resisted exercise machine. Evaluation of aggression and quality of life is assessed by questionnaires, VO₂ max is estimated by maximal testing on bike ergometer, and cardiac and respiratory functions are measured by echocardiography and spirometry, respectively. Markers of cardiovascular risk and inflammation and also cortisol and cortisone are assessed in blood, diurnal urine and/or hair samples. Our cohort (BIC), including dropouts, will be an embedded subcohort in a future national registry study in all individuals with gender dysphoria and controls. Data are available on International Statistical Classification of Diseases and Related Health Problems 10^th version diagnostic codes, prescriptions, socioeconomics and causes of death.

ETHICS AND DISSEMINATION

The Regional Committee on Health Research Ethics for Southern Denmark (S-20190108) and the Danish Data Protection Agency (19/27572) approved the study. Signed informed consent will be obtained from all participants. All findings will be published in peer-reviewed journals or at scientific conferences.

TRIAL REGISTRATION NUMBER

NCT04254354.

Hypogonadism and its treatment among prostate cancer survivors

Adult-onset hypogonadism (AOH) is associated with sexual dysfunction, poor bone mineralization, decreased muscle mass, metabolic syndrome disorder, and cognitive suppression. Historically, testosterone has been contraindicated in men with a history of prostate cancer. However, there has been a modern resurgence in re-evaluating this belief. Not only can testosterone be safely utilized to alleviate AOH symptoms in prostate cancer survivors, it has been also touted as a treatment option for aggressive prostatic cancer. While much work remains in understanding the relationship between testosterone and prostate cancer, those who survive this disease should not be automatically turned away from an opportunity to be treated and restored.

Enhanced Skeletal Muscle Oxidative Capacity and Capillary-to-Fiber Ratio Following Moderately Increased Testosterone Exposure in Young Healthy Women

Background: Recently, it was shown that exogenously administered testosterone enhances endurance capacity in women. In this study, our understanding on the effects of exogenous testosterone on key determinants of oxygen transport and utilization in skeletal muscle is expanded.

Methods: In a double-blinded, randomized, placebo-controlled trial, 48 healthy active women were randomized to 10 weeks of daily application of 10 mg of testosterone cream or placebo. Before and after the intervention, VO₂ max, body composition, total hemoglobin (Hb) mass and blood volumes were assessed. Biopsies from the vastus lateralis muscle were obtained before and after the intervention to assess mitochondrial protein abundance, capillary density, capillary-to-fiber (C/F) ratio, and skeletal muscle oxidative capacity.

Results: Maximal oxygen consumption per muscle mass, Hb mass, blood, plasma and red blood cell volumes, capillary density, and the abundance of mitochondrial protein levels (i.e., citrate synthase, complexes I, II, III, IV-subunit 2, IV-subunit 4, and V) were unchanged by the intervention. However, the C/F ratio, specific mitochondrial respiratory flux activating complex I and linked complex I and II, uncoupled respiration and electron transport system capacity, but not leak respiration or fat respiration, were significantly increased following testosterone administration compared to placebo.

Conclusion: This study provides novel insights into physiological actions of increased testosterone exposure on key determinants of oxygen diffusion and utilization in skeletal muscle of women. Our findings show that higher skeletal muscle oxidative capacity coupled to higher C/F ratio could be major contributing factors that improve endurance performance following moderately increased testosterone exposure.

Hypogonadism and cancer survivorship

PURPOSE OF REVIEW

Hypogonadism is highly prevalent among not only patients with a history of prior treatment for cancer, but also among those patients with a new oncologic diagnosis who have not yet received any cancer therapy. Hypogonadism can cause a wide array of signs and symptoms including: deceased muscle mass; increased fat mass; decreased energy, mood, and overall sense of well being; diminished bone mineral density; infertility; and impaired libido and sexual function. This purpose of this manuscript is to review the mechanisms by which cancer and oncologic treatment regimens can adversely affect the hypothalamic pituitary gonadal axis, resulting in hypogonadism. Risks and benefits associated with the treatment of testosterone deficiency are also discussed, which are important considerations for clinicians caring for affected patients.

RECENT FINDINGS

Hypogonadism has a high prevalence in the setting of cancer and is an important survivorship issue. Recent randomized controlled trials confirm testosterone's therapeutic benefits in terms of sexual function, mood body composition, and bone health, but the specific benefits in terms of quality of life are less clear.

SUMMARY

More prospective studies are needed to further delineate the risks, benefits, and overall outcomes of testosterone replacement therapy in patients with cancer and cancer survivors.

Eye-movements during number comparison: Associations to sex and sex hormones

Multi-digit numbers are of a hierarchical nature with whole number magnitudes depending on digit magnitudes. Processing of multi-digit numbers can occur in a holistic or decomposed fashion. The unit-decade compatibility effect during number comparison is often used as a measure of decomposed processing. It refers to the fact that performance is reduced when the larger number contains the smaller unit digit (e.g. 73 vs. 26). It has been demonstrated that women show a larger compatibility effect than men, which is in accordance with their general tendency towards focusing on stimulus details during processing of visual hierarchical stimuli (local processing style). Such a local processing style has been related to higher progesterone and lower testosterone levels. One method to study individual processing styles is eye-tracking. The aim of the present study was to examine whether sex and sex hormones (estradiol, progesterone, testosterone) relate to eye movement behavior in the number comparison task. Unlike previous studies we found no evidence for sex differences in the behavioral compatibility effect. Nevertheless, women look more often and longer at individual digits and show a stronger compatibility effect in fixation durations compared to men, while men show more saccades between numbers than women. Estradiol and progesterone were related to fewer fixations and shorter fixation durations and more saccades between numbers in men, but not in women. Furthermore, the compatibility effect in the number of fixations and fixation durations was negatively related to testosterone in women. In summary, this is the first study to demonstrate sex differences and sex hormone influences on eye gaze behavior during number comparison.

Anabolic-Androgenic Steroid Abuse Impairs Fibrin Clot Lysis

Abuse of anabolic-androgenic steroids (AASs) is suspected to increase the risk of cardiovascular disease (CVD) and cardiovascular mortality in otherwise healthy individuals. AAS abuse may increase the incidence of CVD by altering the hemostatic balance toward a procoagulant state. Studies on the effect of AAS abuse on the fibrinolytic system, however, have either demonstrated a profibrinolytic effect or no effect of AAS abuse, but the overall effect of AAS on fibrinolysis has not been addressed so far. This cross-sectional study investigated the effect of AAS on fibrin clot lysis, fibrin structure, and the hemostatic proteins, potentially affecting these measures in current and former AAS abusers and healthy age-matched controls. The study population consisted of 37 current and 33 former AAS abusers, along with 30 healthy age-matched controls. Fibrin clot lysis, fibrin structure properties, fibrinogen, coagulation factor XIII (FXIII) plasminogen, plasmin inhibitor, plasminogen activator inhibitor-1 (PAI-1), and thrombin activatable fibrinolysis inhibitor (TAFI) were determined. Fibrin clot lysis was significantly reduced in participants abusing AAS compared with former abusers and controls (p < 0.001). Plasma fibrinogen, plasminogen, and plasmin inhibitor were significantly increased in current abusers (p < 0.05). No significant differences were observed with respect to measures of fibrin structure properties, PAI-1, and TAFI (p > 0.05). In conclusion, AAS abuse depresses fibrin clot lysis. This effect is not associated with alterations in fibrin structure but is rather caused by increased plasma concentrations of fibrinogen, FXIII, and plasmin inhibitor. These findings suggest that AAS abuse may be associated with increased thrombotic disease.

Testosterone supplementation upregulates androgen receptor expression and translational capacity during severe energy deficit

Testosterone supplementation during energy deficit promotes whole body lean mass accretion, but the mechanisms underlying that effect remain unclear. To elucidate those mechanisms, skeletal muscle molecular adaptations were assessed from muscle biopsies collected before, 1 h, and 6 h after exercise and a mixed meal (40 g protein, 1 h postexercise) following 14 days of weight maintenance (WM) and 28 days of an exercise- and diet-induced 55% energy deficit (ED) in 50 physically active nonobese men treated with 200 mg testosterone enanthate/wk (TEST) or placebo (PLA) during the ED. Participants (n = 10/group) exhibiting substantial increases in leg lean mass and total testosterone (TEST) were compared with those exhibiting decreases in both of these measures (PLA). Resting androgen receptor (AR) protein content was higher and fibroblast growth factor-inducible 14 (Fn14), IL-6 receptor (IL-6R), and muscle ring-finger protein-1 gene expression was lower in TEST vs. PLA during ED relative to WM (P < 0.05). Changes in inflammatory, myogenic, and proteolytic gene expression did not differ between groups after exercise and recovery feeding. Mechanistic target of rapamycin signaling (i.e., translational efficiency) was also similar between groups at rest and after exercise and the mixed meal. Muscle total RNA content (i.e., translational capacity) increased more during ED in TEST than PLA (P < 0.05). These findings indicate that attenuated proteolysis at rest, possibly downstream of AR, Fn14, and IL-6R signaling, and increased translational capacity, not efficiency, may drive lean mass accretion with testosterone administration during energy deficit.

An Intramuscular Injection of Mixed Testosterone Esters Does Not Acutely Enhance Strength and Power in Recreationally Active Young Men

Purpose: Limited data are available on the acute performance-enhancing effects of single-dose administration of testosterone in healthy humans. Studies of testosterone administrations to healthy humans are rare due to the difficult nature and necessity of close clinical monitoring. However, our unique physiological experimental facilities combined with close endocrinological collaboration have allowed us to safely complete such a study. We tested the hypothesis that an intramuscular injection of 250 mg mixed testosterone esters (TEs) enhances physical performance in strength and power exercises acutely, measured 24 h after injection. Additionally, we investigated whether the basal serum testosterone concentration influences the performance in countermovement jump (CMJ), 30-s all out cycle sprint, and one-arm isometric elbow flexion.

Methods: In a randomized, double-blind, placebo-controlled design, 19 eugonadal men received either a TE (n = 9, 23 ± 1 years, 183 ± 7 cm, 83 ± 10 kg) or a PLA (n = 10, 25 ± 2 years, 186 ± 6 cm, 82 ± 14 kg) injection. Hormonal levels and the performance in CMJ, 30-s all out cycle sprint, and one-arm isometric elbow flexion were measured before and 24 h after injection.

Results: Firstly, an intramuscular injection of 250 mg mixed TEs did not enhance the vertical jump height in a CMJ test, peak power, mean power, and fatigue index in a 30-s all-out cycle sprint or rate of force development and maximal voluntary contraction in a one-arm isometric elbow flexion 24 h post-injection. Secondly, baseline testosterone levels appeared not to influence performance in strength and power exercises to a large extent in healthy, recreationally active young men.

Conclusion: A single intramuscular injection of 250 mg mixed TEs has no acute ergogenic effects on strength and power performance in recreationally active, young men. This novel information has implication for basic physiological understanding. Whether the same applies to an elite athlete population remains to be determined. If so, this would have implications for anti-doping efforts aiming to determine the most cost-efficient testing programs.

Effects of Testosterone on Serum Concentrations, Fat-free Mass, and Physical Performance by Population: A Meta-analysis

Testosterone (T) administration (TA) increases serum T and fat-free mass (FFM). Although TA-mediated increases in FFM may enhance physical performance, the data are largely equivocal, which may be due to differences in study populations, the magnitude of change in serum T and FFM, or the performance metrics. This meta-analysis explored effects of TA on serum T, FFM, and performance. Associations between increases in serum T and FFM were assessed, and whether changes in serum T or FFM, study population, or the performance metrics affected performance was determined. A systematic review of double-blind randomized trials comparing TA versus placebo on serum T, FFM, and performance was performed. Data were extracted from 20 manuscripts. Effect sizes (ESs) were assessed using Hedge's g and a random effects model. Data are presented as ES (95% confidence interval). No significant correlation between changes in serum T and FFM was observed (P = .167). Greater increases in serum T, but not FFM, resulted in larger effects on performance. Larger increases in testosterone (7.26 [0.76-13.75]) and FFM (0.80 [0.20-1.41]) were observed in young males, but performance only improved in diseased (0.16 [0.05-0.28]) and older males (0.19 [0.10-0.29]). TA increased lower body (0.12 [0.07-0.18]), upper body (0.26 [0.11-0.40]), and handgrip (0.13 [0.04-0.22]) strength, lower body muscular endurance (0.38 [0.09-0.68]), and functional performance (0.20 [0.00-0.41]), but not lower body power or aerobic endurance. TA elicits increases in serum T and FFM in younger, older, and diseased males; however, the performance-enhancing effects of TA across studies were small, observed mostly in muscular strength and endurance, and only in older and diseased males.

Laboratory medicine: health evaluation in elite athletes

The need to evaluate the health status of an athlete represents a crucial aim in preventive and protective sports science in order to identify the best diagnostic strategy to improve performance and reduce risks related to physical exercise. In the present review we aim to define the main biochemical and haematological markers that vary significantly during and after sports training to identify risk factors, at competitive and professional levels and to highlight the set up of a specific parameter's panel for elite athletes. Moreover, we also intend to consider additional biomarkers, still under investigation, which could further contribute to laboratory sports medicine and provide reliable data that can be used by athlete's competent staff in order to establish personal attitudes and prevent sports injuries.

The role of iron in mediating testosterone's effects on erythropoiesis in mice

Testosterone stimulates iron-dependent erythropoiesis and suppresses hepcidin. To clarify the role of iron in mediating testosterone's effects on erythropoiesis, we induced iron deficiency in mice by feeding low iron diet. Iron-replete and iron-deficient mice were treated weekly with testosterone propionate or vehicle for 3 weeks. Testosterone treatment increased red cell count in iron-replete mice, but, surprisingly, testosterone reduced red cell count in iron-deficient mice. Splenic stress erythropoiesis was stimulated in iron-deficient mice relative to iron-replete mice, and further increased by testosterone treatment, as indicated by the increase in red pulp area, the number of nucleated erythroblasts, and expression levels of TfR1, GATA1, and other erythroid genes. Testosterone treatment of iron-deficient mice increased the ratio of early-to-late erythroblasts in the spleen and bone marrow, and serum LDH level, consistent with ineffective erythropoiesis. In iron-deficient mice, erythropoietin levels were higher but erythropoietin-regulated genes were generally downregulated relative to iron-replete mice, suggesting erythropoietin resistance. Conclusion: Testosterone treatment stimulates splenic stress erythropoiesis in iron-replete as well as iron-deficient mice. However, testosterone worsens anemia in iron-deficient mice because of ineffective erythropoiesis possibly due to erythropoietin resistance associated with iron deficiency. Iron plays an important role in mediating testosterone's effects on erythropoiesis.

Testosterone deficiency syndrome: Diagnosis and treatment

The testosterone deficiency syndrome (TDS) is a very common clinical and biochemical condition that affects approximately 2-5% men over the age of 40. From a clinical point of view, it is usually associated with decreased sexual desire and activity, erectile dysfunction, low energy and mood swings, along with T<8-12 nmol/l levels. Questionnaires are not useful in screening but may be useful for diagnosis and follow-up. Its diagnosis requires the presentation of multiple hypogonadism symptoms together with two morning T tests below the acceptable limits. LH and SHBG levels can be useful to determine the cause and the free T level, respectively. Contraindications for treatment are active prostate cancer, stage IV heart failure, breast cancer, desired fertility and hematocrit values over 54%. Treatment is based on the cause of TDS, if any, along with testosterone supplementation. The objective is to achieve normal testosterone levels. Follow-up includes clinical history, analysis (PSA, T+SHBG, hematocrit, glucose and lipid profile) and rectal examination, 3, 6 and 12 months after beginning treatment.

Age-dependent effects of testosterone on spatial memory in male rats

Decreased spatial memory is common in aging populations and reduces their quality of life. Although its role is still controversial, low testosterone (T) may contribute to impaired cognition in aged men. This study aimed to identify the role of T in age-related deficiencies in spatial memory among male rats. Young adult (3 months old) and aged (21 months old) Wistar rats were assigned to independent groups: intact, orchidectomized, or orchidectomized + subcutaneous pellets of T propionate. The phases of spatial memory acquisition (4 daily trials/4 days) and spatial memory retention (1 trial/day, 3 and 12 days after acquisition) were evaluated using the Barnes maze. Compared with young adults, aged intact rats took longer to find the goal, made more mistakes, and showed only slight improvements in goal sector exploration across the acquisition period. The young orchidectomized rats showed no improvement in performance over the days during the acquisition phase. T treatment in hormonally deprived old rats produced a small improvement in goal sector exploration and number of errors during the acquisition phase. Meanwhile, in young adults, this treatment improved the goal sector searching in the retention phase (12 days after acquisition training). Our results suggested that age-related spatial memory deficits cannot be entirely explained by the decline in T levels; however, this androgen produced subtle and mild beneficial effects on spatial memory in young and old males. Taken together, our findings suggest age differences in the role of T on spatial memory in males.

Androgens stimulate erythropoiesis through the DNA-binding activity of the androgen receptor in non-hematopoietic cells

BACKGROUND

Androgens function through DNA and non-DNA binding-dependent signalling of the androgen receptor (AR). How androgens promote erythropoiesis is not fully understood.

DESIGN AND METHODS

To identify the androgen signalling pathway, we treated male mice lacking the second zinc finger of the DNA-binding domain of the AR (AR^ΔZF2 ) with non-aromatizable 5α-dihydrotestosterone (5α-DHT) or aromatizable testosterone. To distinguish direct hematopoietic and non-hematopoietic mechanisms, we performed bone marrow reconstitution experiments.

RESULTS

In wild-type mice, 5α-DHT had greater erythroid activity than testosterone, which can be aromatized to estradiol. The erythroid response in wild-type mice following 5α-DHT treatment was associated with increased serum erythropoietin (EPO) and its downstream target erythroferrone, and hepcidin suppression. 5α-DHT had no erythroid activity in AR^ΔZF2 mice, proving the importance of DNA binding by the AR. Paradoxically, testosterone, but not 5α-DHT, suppressed EPO levels in AR^ΔZF2 mice, suggesting testosterone following aromatization may oppose the erythroid-stimulating effects of androgens. Female wild-type mice reconstituted with AR^ΔZF2 bone marrow cells remained responsive to 5α-DHT. In contrast, AR^ΔZF2 mice reconstituted with female wild-type bone marrow cells showed no response to 5α-DHT.

CONCLUSION

Erythroid promoting effects of androgens are mediated through DNA binding-dependent actions of the AR in non-hematopoietic cells, including stimulating EPO expression.

Questioning the evidence behind the Saturation Model for testosterone replacement therapy in prostate cancer

Published in 2009, the Saturation Model suggested that there were limits to which androgen encouraged growth of the prostate. This was, in particular, applied to prostate cancer, where conventional wisdom since Huggins has considered it almost taboo for a patient being treated with cancer to receive testosterone replacement therapy (TRT). Since then, several studies began to investigate the application of TRT in, at first, mild and stable prostate cancer patients. While early reports seem promising, the validity of the Saturation Model had not been addressed. The current review investigates the evidence synthesis behind the Saturation Model, based on its original publication where it was presented. The evidence reviewed includes in vitro, in vivo and clinical studies that were referenced as the basis when the model was presented. Despite promising associations, the evidence employed were troublingly taken out of context in many cases and applied freely in cases where it would be unwise to do so. In light of some shortcomings in evidence synthesis, we advise some caution when applying the Saturation Model in prostate cancer.

Effects of letrozole administration on growth and reproductive performance in Markhoz goat bucklings

This study evaluated the growth performance, testicular and semen characteristics, and hormonal profile of Markhoz (Iranian Angora) bucklings injected with letrozole (LTZ). Twenty-eight 4-4.5 month old bucks were randomly assigned into four groups and received either 0.25 mg/kg body weight (BW) LTZ subcutaneously (sc LTZ) or intramuscularly (im LTZ), and also sc (sc CONT) or im (im CONT) controls every week for 3 months. The study was performed at the beginning of the breeding season in Sanandaj Animal Husbandry Research Station (46.99 °E, 35.31 °N). The results showed that LTZ causes increased final body weight (25.78 ± 1.61 kg), higher average daily gain (104 ± 0.03 g/days), and decreased feed conversion ratio (7.81 ± 2.57) (P < 0.05). The pre-slaughter, hot, and cold carcass weights (27.56 ± 2.40, 11.45 ± 1.07 and 11.11 ± 1.05 kg, respectively) were (P < 0.05) heavier in LTZ groups while other carcass characteristics did not differ between groups. No differences occurred between the groups in biochemical parameters, except high-density lipoprotein levels (35.47 ± 2.43 mg/dL) which was higher in LTZ treatments (P < 0.05). LTZ-treated bucks had larger scrotal circumference (20.12 ± 5.75 cm), higher relative testicular weight (560.91 ± 78.59 mg/100 g BW) and volume (175.5 ± 29.71 cm³), greater diameter of seminiferous tubules (224.5 ± 5.21 μm), and number of Sertoli cells (8.39 ± 0.77) (P < 0.05). Semen volume (0.74 ± 0.16 mL), sperm concentration (2.64 ± 0.19 × 10^-9/mL), total sperm per ejaculate (1.95 ± 0.49 × 10^-9), and semen index (1248 ± 323) increased (P < 0.05) by LTZ treatments, while semen pH (6.77), motility (80.91%), progressive motility (76.75%), viability (83.35%), abnormality (13.70%), acrosome integrity (78.06%), and membrane integrity (80.05%) of sperm remained unaffected. Intratesticular and serum testosterone (T) levels (7.97 ± 0.89 ng/mg protein and 2.47 ± 0.59 ng/mL, respectively), serum luteinizing hormone (LH), growth hormone (GH) levels (1.71 ± 0.24 and 3.62 ± 0.33 ng/mL, respectively) of LTZ groups were elevated, whereas intratesticular and serum estradiol (E2) levels (84.14 ± 8.15 pg/mg protein and 32.33 ± 2.16 pg/mL, respectively) decreased (P < 0.05). No differences were recorded between the sc and im routes of LTZ administration in the measured parameters. To conclude, we have found that LTZ treatment improves growth and reproductive functions of goat bucklings associated with increased serum LH and GH, elevated T and reduced E2 levels in both serum and testis.

Effects of Testosterone Supplementation on Ghrelin and Appetite During and After Severe Energy Deficit in Healthy Men

BACKGROUND

Severe energy deficits cause interrelated reductions in testosterone and fat free mass. Testosterone supplementation may mitigate those decrements, but could also reduce circulating concentrations of the orexigenic hormone ghrelin, thereby exacerbating energy deficit by suppressing appetite.

OBJECTIVE

To determine whether testosterone supplementation during severe energy deficit influences fasting and postprandial ghrelin concentrations and appetite.

DESIGN AND METHODS

Secondary analysis of a randomized, double-blind trial that determined the effects of testosterone supplementation on body composition changes during and following severe energy deficit in nonobese, eugonadal men. Phase 1 (PRE-ED): 14-day run-in; phase 2: 28 days, 55% energy deficit with 200 mg testosterone enanthate weekly (TEST; n = 24) or placebo (PLA; n = 26); phase 3: free-living until body mass recovered (end-of-study; EOS). Fasting and postprandial acyl ghrelin and des-acyl ghrelin concentrations and appetite were secondary outcomes measured during the final week of each phase.

RESULTS

Fasting acyl ghrelin concentrations, and postprandial acyl and des-acyl ghrelin concentrations increased in PLA during energy deficit then returned to PRE-ED values by EOS, but did not change in TEST (phase-by-group, P < 0.05). Correlations between changes in free testosterone and changes in fasting acyl ghrelin concentrations during energy deficit (ρ = -0.42, P = 0.003) and body mass recovery (ρ = -0.38; P = 0.01) were not mediated by changes in body mass or body composition. Transient increases in appetite during energy deficit were not affected by testosterone treatment.

CONCLUSIONS

Testosterone supplementation during short-term, severe energy deficit in healthy men prevents deficit-induced increases in circulating ghrelin without blunting concomitant increases in appetite.

CLINICAL TRIALS REGISTRATION

www.clinicaltrials.gov NCT02734238 (registered 12 April 2016).

Fiber type-specific hypertrophy and increased capillarization in skeletal muscle following testosterone administration in young women

It is well established that testosterone administration induces muscle fiber hypertrophy and myonuclear addition in men; however, it remains to be determined whether similar morphological adaptations can be achieved in women. The aim of the present study was therefore to investigate whether exogenously administered testosterone alters muscle fiber morphology in skeletal muscle of young healthy, physically active women. Thirty-five young (20-35 yr), recreationally trained women were randomly assigned to either 10-wk testosterone administration (10 mg daily) or placebo. Before and after the intervention, hormone concentrations and body composition were assessed, and muscle biopsies were obtained from the vastus lateralis. Fiber type composition, fiber size, satellite cell and myonuclei content, as well as muscle capillarization were assessed in a fiber type-specific manner by immunohistochemistry. After the intervention, testosterone administration elevated serum testosterone concentration (5.1-fold increase, P = 0.001) and induced significant accretion of total lean mass (+1.9%, P = 0.002) and leg lean mass (+2.4%, P = 0.001). On the muscle fiber level, testosterone increased mixed-fiber cross-sectional area (+8.2%, P = 0.001), an effect primarily driven by increases in type II fiber size (9.2%, P = 0.006). Whereas myonuclei content remained unchanged, a numerical increase (+30.8%) was found for satellite cells associated with type II fibers in the Testosterone group. In parallel with fiber hypertrophy, testosterone significantly increased capillary contacts (+7.5%, P = 0.015) and capillary-to-fiber ratio (+9.2%, P = 0.001) in type II muscle fibers. The present study provides novel insight into fiber type-specific adaptations present already after 10 wk of only moderately elevated testosterone levels in women.NEW & NOTEWORTHY We have recently demonstrated performance-enhancing effects of moderately elevated testosterone concentrations in young women. Here we present novel evidence that testosterone alters muscle morphology in these women, resulting in type II fiber hypertrophy and improved capillarization. Our findings suggest that low doses of testosterone potently impact skeletal muscle after only 10 wk. These data provide unique insights into muscle adaptation and support the performance-enhancing role of testosterone in women on the muscle fiber level.

Hypogonadism in Exercising Males: Dysfunction or Adaptive-Regulatory Adjustment?

For decades researchers have reported men who engaged in intensive exercise training can develop low resting testosterone levels, alterations in their hypothalamic-pituitary-gonadal (HPG) axis, and display hypogonadism. Recently there is renewed interest in this topic since the International Olympic Committee (IOC) Medical Commission coined the term "Relative Energy Deficiency in Sports" (RED-S) as clinical terminology to address both the female-male occurrences of reproductive system health disruptions associated with exercise. This IOC Commission action attempted to move beyond the sex-specific terminology of the "Female Athlete Triad" (Triad) and heighten awareness/realization that some athletic men do have reproductive related physiologic disturbances such as lowered sex hormone levels, HPG regulatory axis alterations, and low bone mineral density similar to Triad women. There are elements in the development and symptomology of exercise-related male hypogonadism that mirror closely that of women experiencing the Triad/RED-S, but evidence also exists that dissimilarities exist between the sexes on this issue. Our research group postulates that the inconsistency and differences in the male findings in relation to women with Triad/RED-S are not just due to sex dimorphism, but that there are varying forms of exercise-related reproductive disruptions existing in athletic men resulting in them displaying a relative hypogonadism condition. Specifically, such conditions in men may derive acutely and be associated with low energy availability (Triad/RED-S) or excessive training load (overtraining) and appear transient in nature, and resolve with appropriate clinical interventions. However, manifestations of a more chronic based hypogonadism that persists on a more permanent basis (years) exist and is termed the "Exercise Hypogonadal Male Condition." This article presents an up-to-date overview of the various types of acute and chronic relative hypogonadism found in athletic, exercising men and proposes mechanistic models of how these various forms of exercise relative hypogonadism develop.

The impact of nandrolone decanoate abuse on experimental animal model: Hormonal and biochemical assessment

Nandrolone decanoate (ND) is one of the most commonly abused anabolic androgenic steroids compounds in the world owing to its ability to improve physical performance but its abuse is associated with several adverse effects. The current study was performed to evaluate the effect of recommended and overdose of nandrolone decanoate (ND) for short and long term on the alterations of biochemical markers related to kidney, liver, adrenal, thyroid gland functions and oxidant and antioxidant activities. Sixty male rats were randomly assigned into two major groups. The first was treated with ND for 6 weeks and the second was treated with same drug for 12 weeks. Each of these groups was further subdivided into three sub groups: 1-Control (untreated rats), 2- Rats intraperitoneally injected with ND 3 mg/kg weekly, 3- Rats intraperitoneally injected with ND 15 mg/kg weekly. Administration of high ND dose for either short or long term significantly elevated kidney function biomarkers, liver enzymes both in serum, cytosol and mitochondria, insignificantly increased thyroid function, significantly increased adrenal function while, decreased ACTH. Moreover, oxidative stress biomarkers were significantly upregulated associated with depression in antioxidants activities. Administration of high ND dose for either short or long term as well as the repeated use of recommended ND dose for long term proved to have harmful effects manifested in impairing the functions of kidneys, liver, thyroid and adrenal glands as well as oxidant antioxidant balance.

Donor Deferral Due to Low Hemoglobin-An Updated Systematic Review

Blood donors attending a donation session may be deferred from donating blood due to a failure to meet low hemoglobin (Hb) thresholds. This costs the blood donor service and donors valuable time and resources. In addition, donors who are deferred may have more symptoms, and as a direct and/or indirect effect of their experience, return rates of donors deferred for low Hb are reduced, even in repeat donors. It is therefore vital that low Hb deferral (LHD) is minimized. The aim of this updated systematic review is to expand the evidence base for factors which affect a donor's risk of deferral due to low Hb. Studies were identified by searching MEDLINE, Embase, The Cochrane Library, and the WHO International Clinical Trials Registry to March 2019. Demographic data, donor history, hematological/biological factors, and the primary outcome of deferral due to low Hb were extracted. Our primary outcome was deferral due to low Hb. Analyses were descriptive and quantitative; pooled odds ratios (ORs) and 95% confidence intervals (CIs) were obtained by meta-analysis using random-effects models. A total of 116 studies met the inclusion criteria. Meta-analysis showed a significantly greater risk of LHD in females compared with males in studies applying universal Hb thresholds for males and females (OR 14.62 95% CI 12.43-17.19) and in those which used sex-specific thresholds (OR 5.73, 95% CI 4.36-7.53). Higher rates of LHD were also associated with increasing age in men, low body weight, shorter interdonation interval, donors of Hispanic or African descent, higher ambient temperature, donors with low ferritin levels, and donation in a fixed donor center. There was conflicting evidence on the effect of new and repeat donor status, and blood group. This work has strengthened the evidence of the previous review in identifying factors that should be considered in studies of donor deferral and highlighting areas in need of further study, including ABO and Rh blood groups, previous platelet donation, diet, smoking, time of day, and genetic data. These factors may lead to individually tailored donation criteria for safe and efficient donation in the future.

Bone health in adult trans persons: an update of the literature

PURPOSE OF REVIEW

Hormonal treatment in trans persons can affect bone health. In this review, recent studies published on this topic in adults are discussed.

RECENT FINDINGS

Before starting hormonal treatment, trans women were found to have lower bone mineral density than cis men, which seems to be related to lower vitamin D concentrations and lower lean body mass, whereas this was not found in trans men. Short-term and long-term studies show that hormonal treatment does not have detrimental effects on bone mineral density in trans women and trans men. Low estradiol concentrations were associated with a decrease in bone mineral density in trans women.

SUMMARY

Based on the reassuring findings in these studies, regularly assessing bone mineral density during hormonal treatment does not seem necessary. This confirms the Endocrine Society Guideline stating that bone mineral density should be measured only when risk factors for osteoporosis exist, especially in people who stop hormonal treatment after gonadectomy. The relationship with estradiol concentrations indicate that hormone supplementation should be adequate and therapy compliance should be stimulated. As vitamin D deficiency frequently occurs, vitamin D supplementation should be considered. Future research should focus on fracture risk and long-term changes in bone geometry.

Testosterone therapy induces molecular programming augmenting physiological adaptations to resistance exercise in older men

BACKGROUND

The andropause is associated with declines in serum testosterone (T), loss of muscle mass (sarcopenia), and frailty. Two major interventions purported to offset sarcopenia are anabolic steroid therapies and resistance exercise training (RET). Nonetheless, the efficacy and physiological and molecular impacts of T therapy adjuvant to short-term RET remain poorly defined.

METHODS

Eighteen non-hypogonadal healthy older men, 65-75 years, were assigned in a random double-blinded fashion to receive, biweekly, either placebo (P, saline, n = 9) or T (Sustanon 250 mg, n = 9) injections over 6 week whole-body RET (three sets of 8-10 repetitions at 80% one-repetition maximum). Subjects underwent dual-energy X-ray absorptiometry, ultrasound of vastus lateralis (VL) muscle architecture, and knee extensor isometric muscle force tests; VL muscle biopsies were taken to quantify myogenic/anabolic gene expression, anabolic signalling, muscle protein synthesis (D₂ O), and breakdown (extrapolated).

RESULTS

Testosterone adjuvant to RET augmented total fat-free mass (P=0.007), legs fat-free mass (P=0.02), and appendicular fat-free mass (P=0.001) gains while decreasing total fat mass (P=0.02). Augmentations in VL muscle thickness, fascicle length, and quadriceps cross-section area with RET occured to a greater extent in T (P < 0.05). Sum strength (P=0.0009) and maximal voluntary contract (e.g. knee extension at 70°) (P=0.002) increased significantly more in the T group. Mechanistically, both muscle protein synthesis rates (T: 2.13 ± 0.21%·day^-1 vs. P: 1.34 ± 0.13%·day^-1 , P=0.0009) and absolute breakdown rates (T: 140.2 ± 15.8 g·day^-1 vs. P: 90.2 ± 11.7 g·day^-1 , P=0.02) were elevated with T therapy, which led to higher net turnover and protein accretion in the T group (T: 8.3 ± 1.4 g·day^-1 vs. P: 1.9 ± 1.2 g·day^-1 , P=0.004). Increases in ribosomal biogenesis (RNA:DNA ratio); mRNA expression relating to T metabolism (androgen receptor: 1.4-fold; Srd5a1: 1.6-fold; AKR1C3: 2.1-fold; and HSD17β3: two-fold); insulin-like growth factor (IGF)-1 signalling [IGF-1Ea (3.5-fold) and IGF-1Ec (three-fold)] and myogenic regulatory factors; and the activity of anabolic signalling (e.g. mTOR, AKT, and RPS6; P < 0.05) were all up-regulated with T therapy. Only T up-regulated mitochondrial citrate synthase activity (P=0.03) and transcription factor A (1.41 ± 0.2-fold, P=0.0002), in addition to peroxisome proliferator-activated receptor-γ co-activator 1-α mRNA (1.19 ± 0.21-fold, P=0.037).

CONCLUSIONS

Administration of T adjuvant to RET enhanced skeletal muscle mass and performance, while up-regulating myogenic gene programming, myocellular translational efficiency and capacity, collectively resulting in higher protein turnover, and net protein accretion. T coupled with RET is an effective short-term intervention to improve muscle mass/function in older non-hypogonadal men.

Relationship between body composition and hormone sensitivity for androgen deprivation therapy in patients with metastatic prostate cancer

Background

To evaluate the relationship between body composition and the oncological outcome of androgen deprivation therapy (ADT), we investigated whether body composition features including the psoas muscle may be predictive factors of ADT.

Methods

This study enrolled patients with hormone-naïve metastatic prostate cancer who were treated with primary ADT from April 1996 to November 2013 at Kyushu University Hospital and who underwent a computed tomography scan before primary ADT for calculating body fat percentage, psoas muscle ratio (psoas muscle, cm³/height, cm), and body mass index.

Results

Of the 178 patients enrolled, 60 patients died during follow-up. Median follow-up was 32 months, and progression-free survival and overall survival (OS) were 28 and 80 months, respectively. Multivariate analysis revealed that the psoas muscle ratio was correlated with OS (hazard ratio: 0.448; 95% confidence interval = 0.206–0.922; p = 0.028).

Conclusions

This study demonstrated that higher psoas muscle ratio predicts longer OS among patients with nonlocalized prostate cancer treated with primary ADT.

Short-term effect of pharmacologically induced alterations in testosterone levels on common blood biomarkers in a controlled healthy human model

Testosterone deficiency in males is associated with serious comorbidities such as cardiovascular disease, diabetes type two, and also an increased risk of premature death. The pathogenetic mechanism behind this association, however, has not yet been clarified and is potentially bidirectional. The aim of this clinical trial was to gain insight into the short-term effect of changes in testosterone on blood analytes in healthy young men. Thirty healthy young male volunteers were recruited and monitored in our designed human model. Blood sampling was performed prior to and 3 weeks after pharmacological castration with a gonadotropin-releasing hormone antagonist. Subsequently, testosterone replacement with 1000 mg testosterone undecanoate was given and additional blood samples were collected 2 weeks later. The alterations in the levels of 37 routine biomarkers were statistically analysed. Eight biomarkers changed significantly in a similar manner as testosterone between the time points (e.g. prostate specific antigen, creatinine and magnesium), whereas seven other markers changed in the inverse manner as testosterone, including sexual hormone-binding globulin, urea, aspartate aminotransferase and alanine aminotransferase. Most of our results were supported by data from other studies. The designed controlled human model yielded changes in known biomarkers suggesting that low testosterone has a negative effect on health in young healthy men.

Testosterone replacement in young male cancer survivors: A 6-month double-blind randomised placebo-controlled trial

BACKGROUND

Young male cancer survivors have lower testosterone levels, higher fat mass, and worse quality of life (QoL) than age-matched healthy controls. Low testosterone in cancer survivors can be due to orchidectomy or effects of chemotherapy and radiotherapy. We have undertaken a double-blind, placebo-controlled, 6-month trial of testosterone replacement in young male cancer survivors with borderline low testosterone (7-12 nmol/l).

METHODS AND FINDINGS

This was a multicentre United Kingdom study conducted in secondary care hospital outpatients. Male survivors of testicular cancer, lymphoma, and leukaemia aged 25-50 years with morning total serum testosterone 7-12 nmol/l were recruited. A total of 136 men were randomised between July 2012 and February 2015 (42.6% aged 25-37 years, 57.4% 38-50 years, 88% testicular cancer, 10% lymphoma, matched for body mass index [BMI]). Participants were randomised 1:1 to receive testosterone (Tostran 2% gel) or placebo for 26 weeks. A dose titration was performed after 2 weeks. The coprimary end points were trunk fat mass and SF36 Physical Functioning score (SF36-PF) at 26 weeks by intention to treat. At 26 weeks, testosterone treatment compared with placebo was associated with decreased trunk fat mass (-0.9 kg, 95% CI -1.6 to -0.3, p = 0.0073), decreased whole-body fat mass (-1.8 kg, 95% CI -2.9 to -0.7, p = 0.0016), and increased lean body mass (1.5 kg, 95% CI 0.9-2.1, p < 0.001). Decrease in fat mass was greatest in those with a high truncal fat mass at baseline. There was no treatment effect on SF36-PF or any other QoL scores. Testosterone treatment was well tolerated. The limitations of our study were as follows: a relatively short duration of treatment, only three cancer groups included, and no hard end point data such as cardiovascular events.

CONCLUSIONS

In young male cancer survivors with low-normal morning total serum testosterone, replacement with testosterone is associated with an improvement in body composition.

TRIAL REGISTRATION

ISRCTN: 70274195, EudraCT: 2011-000677-31.