Serum testosterone, dihydrotestosterone and estradiol concentrations in older men self-reporting very good health: the healthy man study

Sex steroids and androgen biomarkers in the healthy man study: within-person variability and impact of fasting

OBJECTIVE

Serum testosterone measurements in clinical practice mostly utilize "direct" (non-extraction) immunoassays which have method-specific bias due to steroid cross-reactivity and nonspecific matrix artifacts. Although more accurate, sensitive, and specific liquid chromatography-mass spectrometry (LCMS) dominates in clinical research, the within-person variability of serum testosterone in healthy men using LCMS measurement is not reported.

DESIGN

Longitudinal multi-sampling observational study of men in excellent health over 3 months.

METHODS

Elite healthy men (n = 325) over 40 years of age in excellent, asymptomatic health provided 9 blood samples over 3 months with serum testosterone, dihydrotestosterone (DHT), estradiol (E2), and estrone (E1) measured by validated LCMS with conventional biochemical and anthropometric variables.

RESULTS

Quantitative estimates of within-person variability within day and between day, week, month, and quarter were stable other than an increase due to fasting. The androgen biomarkers most sensitive to age and testosterone among widely used biochemical and anthropometric variables in middle-aged and older men were identified.

CONCLUSIONS

This study provides estimates of variability in serum testosterone and the best androgen biomarkers that may prove useful for future studies of androgen action in male ageing.

In vitro binding analysis of legacy-linear and new generation-cyclic perfluoro-alkyl substances on sex hormone binding globulin and albumin, suggests low impact on serum hormone kinetics of testosterone

In humans, serum testosterone (T) is largely bound to the sex hormone binding globulin (SHBG) and human serum albumin (hSA), resulting in a 2-3 % of unbound or "free" active quote (FT). Endocrine-disrupting chemicals, including perfluoro-alkyl substances (PFAS), are recognized to interfere with the hormonal axes, but the possible impact on the FT quote has not been addressed so far. Here we investigated the possible competition of two acknowledged PFAS molecules on T binding to SHBG and hSA. In particular, perfluoro-octanoic acid (PFOA) and acetic acid, 2,2-difluoro-2-((2,2,4,5-tetrafluoro-5(trifluoromethoxy)-1,3-dioxolan-4-yl)oxy)-ammonium salt (1:1) (C6O4) were used as, respectively, legacy-linear and new-generation-cyclic PFASs. Human recombinant SHBG 30-234 domain (SHBG30-234), produced in HEK293-F cells, and delipidated recombinant hSA were used as in vitro protein models. Isothermal Titration Calorimetry (ITC) and tryptophan fluorescence quencing (TFQ) were used to evaluate the binding modes of T and PFAS to SHBG30-234 and hSA. ITC revealed the binding of T to SHBG30-234 with a Kd of 44 ± 2 nM whilst both PFOA and C6O4 showed no binding activity. Results were confirmed by TFQ, since only T modified the fluorescence profile of SHBG30-234. In hSA, TFQ confirmed the binding of T on FA6 site of the protein. A similar binding mode was observed for PFOA but not for C6O4, as further verified by displacement experiments with T. Although both PFASs were previously shown to bind hSA, only PFOA is predicted to possibly compete with T for the binding to hSA. However, on the base of the binding stoichiometry and affinity of PFOA for hSA, this appears unlikely at the blood concentrations of the chemical documented to date.

Factors Associated With Circulating Sex Hormones in Men : Individual Participant Data Meta-analyses

BACKGROUND

Various factors modulate circulating testosterone in men, affecting interpretation of testosterone measurements.

PURPOSE

To clarify factors associated with variations in sex hormone concentrations.

DATA SOURCES

Systematic literature searches (to July 2019).

STUDY SELECTION

Prospective cohort studies of community-dwelling men with total testosterone measured using mass spectrometry.

DATA EXTRACTION

Individual participant data (IPD) (9 studies; n = 21 074) and aggregate data (2 studies; n = 4075). Sociodemographic, lifestyle, and health factors and concentrations of total testosterone, sex hormone-binding globulin (SHBG), luteinizing hormone (LH), dihydrotestosterone, and estradiol were extracted.

DATA SYNTHESIS

Two-stage random-effects IPD meta-analyses found a nonlinear association of testosterone with age, with negligible change among men aged 17 to 70 years (change per SD increase about the midpoint, -0.27 nmol/L [-7.8 ng/dL] [CI, -0.71 to 0.18 nmol/L {-20.5 to 5.2 ng/dL}]) and decreasing testosterone levels with age for men older than 70 years (-1.55 nmol/L [-44.7 ng/dL] [CI, -2.05 to -1.06 nmol/L {-59.1 to -30.6 ng/dL}]). Testosterone was inversely associated with body mass index (BMI) (change per SD increase, -2.42 nmol/L [-69.7 ng/dL] [CI, -2.70 to -2.13 nmol/L {-77.8 to -61.4 ng/dL}]). Testosterone concentrations were lower for men who were married (mean difference, -0.57 nmol/L [-16.4 ng/dL] [CI, -0.89 to -0.26 nmol/L {-25.6 to -7.5 ng/dL}]); undertook at most 75 minutes of vigorous physical activity per week (-0.51 nmol/L [-14.7 ng/dL] [CI, -0.90 to -0.13 nmol/L {-25.9 to -3.7 ng/dL}]); were former smokers (-0.34 nmol/L [-9.8 ng/dL] [CI, -0.55 to -0.12 nmol/L {-15.9 to -3.5 ng/dL}]); or had hypertension (-0.53 nmol/L [-15.3 ng/dL] [CI, -0.82 to -0.24 nmol/L {-23.6 to -6.9 ng/dL}]), cardiovascular disease (-0.35 nmol/L [-10.1 ng/dL] [CI, -0.55 to -0.15 nmol/L {-15.9 to -4.3 ng/dL}]), cancer (-1.39 nmol/L [-40.1 ng/dL] [CI, -1.79 to -0.99 nmol/L {-51.6 to -28.5 ng/dL}]), or diabetes (-1.43 nmol/L [-41.2 ng/dL] [CI, -1.65 to -1.22 nmol/L {-47.6 to -35.2 ng/dL}]). Sex hormone-binding globulin was directly associated with age and inversely associated with BMI. Luteinizing hormone was directly associated with age in men older than 70 years.

LIMITATION

Cross-sectional analysis, heterogeneity between studies and in timing of blood sampling, and imputation for missing data.

CONCLUSION

Multiple factors are associated with variation in male testosterone, SHBG, and LH concentrations. Reduced testosterone and increased LH concentrations may indicate impaired testicular function after age 70 years. Interpretation of individual testosterone measurements should account particularly for age older than 70 years, obesity, diabetes, and cancer.

PRIMARY FUNDING SOURCE

Medical Research Future Fund, Government of Western Australia, and Lawley Pharmaceuticals. (PROSPERO: CRD42019139668).

Approach to the Patient: The Evaluation and Management of Men ≥50 Years With Low Serum Testosterone Concentration

Although testosterone replacement in men with classic hypogonadism due to an identified pathology of the hypothalamic-pituitary-testicular axis is uncontroversial, the role of testosterone treatment for men with age-related declines in circulating testosterone is unclear. This is due to the lack of large, long-term testosterone therapy trials assessing definitive clinical endpoints. However, men ≥50 years of age, particularly those who have a body mass index >25 kg/m2 and multiple comorbidities, commonly present with clinical features of androgen deficiency and low serum testosterone concentrations. Clinicians are faced with the question whether to initiate testosterone therapy, a difficult dilemma that entails a benefit-risk analysis with limited evidence from clinical trials. Using a case scenario, we present a practical approach to the clinical assessment and management of such men.

Mechanism associated with changes in male reproductive functions during ageing process

Ageing is a natural process with physiological changes in different body parts and has been associated with decreased reproductive capacity. Factors such as imbalance in the antioxidant defence system, vascular diseases, diabetes mellitus, accessory reproductive glands infection, obesity as well as buildup of toxic substances play a role in age-related male reproductive malfunction. Age is inversely proportional to volume of semen, sperm count, sperm progressive motility, sperm viability, normal sperm morphology. The observed negative correlation between ageing and semen indices contributes to male infertility and reproductive decline. Normal levels of ROS, plays crucial role in facilitating sperm function, such as capacitation, hyper-activation, acrosome reaction as well as sperm-oocyte fusion; however, a substantial elevation in the endogenous level of ROS, especially in reproductive tissues, usually instigates destruction of sperm cells and heightened male infertility. Contrarily, antioxidants, such as vitamins C and E, beta-carotene, and micronutrients like zinc and folate, have been found by researchers to facilitate normal semen quality and male reproductive function. Furthermore, the role of hormonal imbalance as a result of the compromised hypothalamic-pituitary-gonadal axis, Sertoli and Leydig cells disorder, and nitric oxide-medicated erectile dysfunction during ageing cannot be undermined.

Hormones and Aging: An Endocrine Society Scientific Statement

Multiple changes occur across various endocrine systems as an individual ages. The understanding of the factors that cause age-related changes and how they should be managed clinically is evolving. This statement reviews the current state of research in the growth hormone, adrenal, ovarian, testicular, and thyroid axes, as well as in osteoporosis, vitamin D deficiency, type 2 diabetes, and water metabolism, with a specific focus on older individuals. Each section describes the natural history and observational data in older individuals, available therapies, clinical trial data on efficacy and safety in older individuals, key points, and scientific gaps. The goal of this statement is to inform future research that refines prevention and treatment strategies in age-associated endocrine conditions, with the goal of improving the health of older individuals.

Longitudinal Profiling of Endogenous Steroids in Blood Using the Athlete Biological Passport Approach

CONTEXT

Detection of endogenous anabolic androgenic steroids (EAAS), like testosterone (T), as doping agents has been improved with the launch of the Steroidal Module of the Athlete Biological Passport (ABP) in urine samples.

OBJECTIVE

To target doping practices with EAAS, particularly in individuals with low level of biomarkers excreted in urine, by including new target compounds measured in blood.

DESIGN

T and T/androstenedione (T/A4) distributions were obtained from 4 years of anti-doping data and applied as priors to analyze individual profiles from 2 T administration studies in female and male subjects.

SETTING

Anti-doping laboratory. Elite athletes (n = 823) and male and female clinical trials subjects (n = 19 and 14, respectively).

INTERVENTION(S)

Two open-label administration studies were carried out. One involved a control phase period followed by patch and then oral T administration in male volunteers and the other followed female volunteers during 3 menstrual cycles with 28 days of daily transdermal T application during the second month.

MAIN OUTCOME MEASURE(S)

Serum samples were analyzed for T and A4 and the performance of a longitudinal ABP-based approach was evaluated for T and T/A4.

RESULTS

An ABP-based approach set at a 99% specificity flagged all female subjects during the transdermal T application period and 44% of subjects 3 days after the treatment. T showed the best sensitivity (74%) in response to transdermal T application in males.

CONCLUSIONS

Inclusion of T and T/A4 as markers in the Steroidal Module can improve the performance of the ABP to identify T transdermal application, particularly in females.

Hormone measurements and histomorphological observations in male Bactrian camels

The aim of this study was to investigate the effect of age on the hypothalamic-pituitary-gonadal (HPG) axis hormones and to determine the morphological changes of the testis. The Bactrian camels were divided into two groups based on their ages. The results showed that the testicular weight was significantly heavier in adult male camels than in pubertal male camels (P < 0.05). There were also significant differences between testicular length, testicular width, and testicular volume (P < 0.05). In the testes of both pubertal and adult male camels, Sertoli cells, spermatogonia, spermatocytes, round spermatids, and elongated spermatids were observed. Adult male camels had more Sertoli cells (P < 0.01) and elongated spermatids (P < 0.05). The concentrations of testosterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were higher in the plasma and testes of adult camels than in pubertal camels (P < 0.05). E2 concentrations were lower in adult camels than in pubertal camels (P < 0.05). The testosterone levels in testicular tissue were higher than in blood plasma in both adult and pubertal stage (P < 0.05). In conclusion, these findings provide supportive knowledge and show the significant differences in terms of testicular volume, testicular hormone concentrations, and testicular morphology between different developmental stages in Bactrian camels.

Relationship between testosterone-estradiol ratio and some anthropometric and metabolic parameters among Nigerian men

Background

Alterations in sex hormone levels are implicated in the regulation of metabolic processes in men. In recent years, the prevalence of metabolic disorders, such as obesity, insulin resistance, and type 2 diabetes, has risen in Nigeria. In men, these disorders may be associated with the ratio of serum testosterone to estradiol levels. Therefore, we investigated the relationship between the testosterone-estradiol (T/E2) ratio, anthropometry, and metabolic parameters in Nigerian men.

Method

Eighty-five adult men were recruited for this study. Participants' data such as age, weight, height, BMI, and waist circumference were collected. Plasma total testosterone and estradiol levels, as well as metabolic parameters such as fasting blood sugar, creatinine, urea, HDL cholesterol, total cholesterol, and triglycerides levels, were determined. The data were analyzed using SPSS version 25 software.

Results

Anthropometric parameters such as weight, height, BMI, and waist circumference showed a negative correlation with plasma T/E2 (r = -0.265, -0.288, -0.106, -0.204; p = 0.007, 0.004, 0.167, 0.061 respectively). However, the T/E2 ratio showed a positive correlation with the metabolic parameters such as fasting blood sugar, HDL cholesterol levels, plasma creatinine, and urea (r = 0.219, 0.096, 0.992, 0.152; p = 0.022, 0.192, <0.001, 0.082 respectively), while there were negative correlations with total cholesterol and triglycerides levels (r = -0.200, -0.083; p = 0.034, 0.226 respectively).

Conclusion

These findings show that there are significant correlations between the T/E2 ratio and weight, height, fasting blood sugar, creatinine, and urea, while there are no significant correlations between T/E2 ratio and BMI, waist circumference, HDL-cholesterol, and triglycerides.

Greater Ecologically Assessed Positive Experiences Predict Heightened Sex Hormone Concentrations Across Two Weeks in Older Adults

OBJECTIVES

Sex hormones are important components of healthy aging, with beneficial effects on physical and mental health. Positive experiences such as elevated mood, lowered stress, and higher well-being also contribute to health outcomes and, in younger adults, may be associated with elevated sex hormone levels. However, little is known about the association between positive experiences and sex hormones in older adults.

METHODS

In this study, older men and women (N = 224, 70+ years of age) provided blood samples before and after a 2-week period of ecological momentary assessment (EMA) of positive and negative experiences (assessed based on self-reporting items related to affect, stress, and well-being). Concentrations of a panel of steroid sex hormones and glucocorticoids were determined in blood.

RESULTS

Higher levels of positive experiences reported in daily life across 2 weeks were associated with increases in free (biologically active) levels of testosterone (B = 0.353 [0.106, 0.601], t(221.3) = 2.801, p = .006), estradiol (B = 0.373 [0.097, 0.649], t(225.1) = 2.645, p = .009), and estrone (B = 0.468 [0.208, 0.727], t(224.3) = 3.535, p < .001) between the start and the end of the 2-week EMA period.

DISCUSSION

These findings suggest that sex hormones may be a pathway linking positive experiences to health in older adults.

Analysis of factors affecting testicular spermatogenesis capacity by using the tissue transcriptome data from GTEx

In human, endo- or exogeneous factors might alter the cellular composition, the endocrine and inflammatory micro-environments and the metabolic balance in testis. These factors will further impair the testicular spermatogenesis capacity and alter the transcriptome of testis. Conversely, it should be possible that the alteration of the transcriptomes in testes be used as an indicator to evaluate the testicular spermatogenesis capacity and to predict the causing factors. In this study, using the transcriptome data of human testes and whole blood which were collected by the genotype-tissue expression project (GTEx), we analyzed the transcriptome differences in human testes and explored those factors that affecting spermatogenesis. As a result, testes were clustered into five clusters according to their transcriptomic features, and each cluster of testes was evaluated as having different spermatogenesis capacity. High rank genes of each cluster and the differentially expressed genes in lower functional testes were analyzed. Transcripts in whole blood which may be associated with testis function were also analyzed by the correlation test. As a result, factors such as immune response, oxygen transport, thyrotropin, prostaglandin and tridecapeptide neurotensin were found associated with spermatogenesis. These results revealed multiple clues about the spermatogenesis regulation in testis and provided potential targets to improve the fertility of men in clinic.

Age-related decrease in serum dihydrotestosterone concentration is accompanied by impaired vascular status

INTRODUCTION

The effect of androgens on the cardiovascular system in humans is ambiguous. Moreover, still little is known about the effects of the most potent androgen, dihydrotestosterone, on arterial stiffness and endothelial function. The aim of this study was to evaluate whether age-dependent alterations in serum concentration of dihydrotestosterone and its circulating metabolite are accompanied by changes in endothelial function and arterial stiffness.

METHODS

In 12 young and 11 older men, basal serum concentrations of testosterone, dehydroepiandrosterone sulfate (DHAE-S), androstenedione (AE), dihydrotestosterone (DHT) and androstanediol glucuronide (ADG) were analyzed in relation to vascular status including cIMT - carotid intima media thickness, cAI - central augmentation index, crPWV - carotid radial pulse wave velocity, SI - stiffness index, endothelial and inflammatory markers.

RESULTS

Although concentration of testosterone was not different between young and older group, it was demonstrated that DHT, DHEA-S, AE and ADG were significantly lower in older men in comparison to young men (p < 0.01). Interestingly the most surprising difference was found for DHT concentration, that was as much as 61 % lower in aged men that displayed significantly higher values of cIMT, AI, crPWV and SI (p < 10^-4), suggestive of arterial stiffness. Furthermore, DHT was negatively correlated to all arterial wall parameters (cAI, crPWV, SI and cIMT), c-reactive protein (CRP) and hyaluronic acid (HA) concentration, as well as positively correlated to markers of endothelial function (MNA and 6-keto-PGF_1α) in all studied individuals (n = 23).

CONCLUSIONS

We have shown that ageing leads to a significant decrease in DHT concentration that is accompanied by impaired arterial wall characteristics and worsened endothelial function. Therefore more attention should be paid to the DHT, DHEA-S and ADG concentrations as a biomarkers for vascular dysfunction in ageing men.

Dysfunctional Lipid Metabolism-The Basis for How Genetic Abnormalities Express the Phenotype of Aggressive Prostate Cancer

Prostate cancer is the second most frequent cancer in men, with increasing prevalence due to an ageing population. Advanced prostate cancer is diagnosed in up to 20% of patients, and, therefore, it is important to understand evolving mechanisms of progression. Significant morbidity and mortality can occur in advanced prostate cancer where treatment options are intrinsically related to lipid metabolism. Dysfunctional lipid metabolism has long been known to have a relationship to prostate cancer development; however, only recently have studies attempted to elucidate the exact mechanism relating genetic abnormalities and lipid metabolic pathways. Contemporary research has established the pathways leading to prostate cancer development, including dysregulated lipid metabolism-associated de novo lipogenesis through steroid hormone biogenesis and β-oxidation of fatty acids. These pathways, in relation to treatment, have formed potential novel targets for management of advanced prostate cancer via androgen deprivation. We review basic lipid metabolism pathways and their relation to hypogonadism, and further explore prostate cancer development with a cellular emphasis.

Obesity, type 2 diabetes, and testosterone in ageing men

In the absence of obesity, adverse lifestyle behaviours, and use of medication such as opioids serum testosterone concentrations decrease by only a minimal amount at least until very advanced age in most men. Obesity is heterogeneous in its phenotype, and it is the accumulation of excess adipose tissue viscerally associated with insulin resistance, dyslipidaemia, inflammation, hypothalamic leptin resistance and gliosis that underpins the functional hypogonadism of obesity. Both central (hypothalamic) and peripheral mechanisms are involved resulting in a low serum total testosterone concentration, while LH and FSH are typically in the normal range. Peripherally a decrease in serum sex hormone binding globulin (SHBG) concentration only partially explains the decrease in testosterone and there is increasing evidence for direct effects in the testis. Men with obesity associated functional hypogonadism and serum testosterone concentrations below 16 nmol/L are at increased risk of incident type 2 diabetes (T2D); high testosterone concentrations are protective. The magnitude of weight loss is linearly associated with an increase in serum testosterone concentration and with the likelihood of preventing T2D or reverting newly diagnosed disease; treatment with testosterone for 2 years increases the probability of a positive outcome from a lifestyle intervention alone by approximately 40%. Whether the additional favourable benefits of testosterone treatment on muscle mass and strength and bone density and quality in the long-term remains to be determined.

Reproductive axis ageing and fertility in men

Compared to women, increasing male age is not accompanied by such marked changes in reproductive function but changes certainly do happen. These include alterations to the hypothalamo-pituitary-testicular axis, with resultant implications for testosterone production and bioavailability as well as spermatogenesis. There is a decline in sexual function as men age, with a dramatic increase in the prevalence of erectile dysfunction after the age of 40, which is a marker for both clinically evident as well as covert coronary artery disease. Despite a quantitative decline in spermatogenesis and reduced fecundability, the male potential for fertility persists throughout adult life, however there are also increasingly recognised alterations in sperm quality and function with significant implications for offspring health. These changes are relevant to both natural and medically assisted conception.

Aging and androgens: Physiology and clinical implications

In men >  ~35 years, aging is associated with perturbations in the hypothalamus-pituitary-testicular axis and declining serum testosterone concentrations. The major changes are decreased gonadotropin-releasing hormone (GnRH) outflow and decreased Leydig cell responsivity to stimulation by luteinizing hormone (LH). These physiologic changes increase the prevalence of biochemical secondary hypogonadism-a low serum testosterone concentration without an elevated serum LH concentration. Obesity, medications such as opioids or corticosteroids, and systemic disease further reduce GnRH and LH secretion and might result in biochemical or clinical secondary hypogonadism. Biochemical secondary hypogonadism related to aging often remits with weight reduction and avoidance or treatment of other factors that suppress GnRH and LH secretion. Starting at age ~65-70, progressive Leydig cell dysfunction increases the prevalence of biochemical primary hypogonadism-a low serum testosterone concentration with an elevated serum LH concentration. Unlike biochemical secondary hypogonadism in older men, biochemical primary hypogonadism is generally irreversible. The evaluation of low serum testosterone concentrations in older men requires a careful assessment for symptoms, signs and causes of male hypogonadism. In older men with a body mass index (BMI) ≥ 30, biochemical secondary hypogonadism and without an identifiable cause of hypothalamus or pituitary pathology, weight reduction and improvement of overall health might reverse biochemical hypogonadism. For older men with biochemical primary hypogonadism, testosterone replacement therapy might be beneficial. Because aging is associated with decreased metabolism of testosterone and increased tissue-specific androgen sensitivity, lower dosages of testosterone replacement therapy are often effective and safer in older men.

Ageing male (part I): Pathophysiology and diagnosis of functional hypogonadism

This narrative review summarizes key points of the pathogenesis and diagnosis of the ageing-related decline of testosterone (T) in men. The condition is commonly termed late-onset hypogonadism (LOH), but because it is more often caused by other factors than chronological ageing (obesity and other comorbidities), a more appropriate term is functional hypogonadism (FH). Unlike the classical organic hypogonadism, no anatomical or genetic aberrations are found in FH, and the suppression of T is milder. Moreover, FH can be reversible if the underlying cause (e.g. obesity, chronic disease) is removed/treated. Low serum total T in connection with more specific hypogonadism-associated symptoms (primarily sexual) form the basis of the diagnosis of FH. When T concentrations are borderline, the accuracy of diagnosis can be improved by assessment of free or calculated free T, especially when suppressed SHBG levels (usually related to obesity) are likely. Current data indicate that FH (low T and sexual symptoms) is not a common condition, and it is detectable in about 2% of community-dwelling men aged 40-80 years.

Use of anti-androgenic 5α-reductase inhibitors and risk of oesophageal and gastric cancer by histological type and anatomical sub-site

Background

To investigate if anti-androgenic medications 5α-reductase inhibitors (5-ARIs) decrease the risk of developing oesophageal and gastric tumours, analysed by histological type and anatomical sub-site.

Methods

A Swedish population-based cohort study between 2005 and 2018 where men using 5-ARIs were considered exposed. For each exposed participant, ten male age-matched non-users of 5-ARIs (non-exposed) were included. Multivariable Cox regression provided hazard ratios (HR) with 95% confidence intervals (CI) adjusted for age, calendar year, smoking, non-steroidal anti-inflammatory drugs/aspirin use, and statins use. Further adjustments were made depending on the tumour analysed.

Results

The cohort included 191,156 users of 5-ARIs and 1,911,560 non-users. Overall, the use of 5-ARIs was not associated with any statistically significantly reduced risk of oesophageal or cardia adenocarcinoma (adjusted HR 0.92, 95% CI 0.82–1.02) or gastric non-cardia adenocarcinoma (adjusted HR 0.90, 95% CI 0.80–1.02). However, the use of 5-ARIs indicated a decreased risk of oesophageal or cardia adenocarcinoma among obese or diabetic participants (adjusted HR 0.55, 95% CI 0.39–0.80) and a reduced risk of oesophageal squamous cell carcinoma (adjusted HR 0.49, 95% CI 0.37–0.65).

Conclusion

Users of 5-ARIs may have a decreased risk of developing oesophageal or cardia adenocarcinoma among those obese or diabetic, and a decreased risk of oesophageal squamous cell carcinoma.

Longitudinal changes in serum testosterone and sex hormone-binding globulin in men aged 40-69 years from the UK Biobank

OBJECTIVE

Testosterone and sex hormone-binding globulin (SHBG) concentrations are reported to decline during male ageing, but whether these changes reflect physiological ageing or age-related comorbidities remains uncertain. We examined longitudinal changes in serum testosterone and SHBG concentrations in middle-aged to older men, concordance between baseline and follow-up values and relationships with concomitant changes in lifestyle and medical factors.

DESIGN

Population-based longitudinal cohort study.

PARTICIPANTS

Community-dwelling men aged 40-69 years.

MEASUREMENTS

Immunoassay serum total testosterone (n = 7812) and SHBG (n = 6491) at baseline (2006-2010) and follow-up (2012-2013). Free testosterone (cFT) was calculated. Bland-Altman analyses and concordance correlation of repeated measurements were conducted. Associations of changes in hormone concentrations with lifestyle and medical factors were explored using Spearman's rank correlation.

RESULTS

Over 4.3 years follow-up, there was a negligible mean change (±SE) in serum total testosterone concentration (+0.06 ± 0.03 nmol/L), whereas mean SHBG concentration increased (+3.69 ± 0.12 nmol/L) and cFT decreased (-10.7 ± 0.7 pmol/L). Concordance estimates were 0.67 (95% confidence interval [CI]: 0.66-0.69) for total testosterone, 0.83 (CI = 0.82-0.84) for SHBG and 0.56 (CI = 0.54-0.58) for cFT. Changes in serum total testosterone correlated with changes in SHBG (Spearman's rank ρ = 0.33, CI = 0.30-0.35), and inversely with changes in body mass index (BMI) (ρ = -0.18, CI = -0.20 to -0.16) and waist circumference (ρ = -0.13, CI = -0.15 to -0.11) and in SHBG with changes in BMI (ρ = -0.34, CI = -0.36 to -0.32) and waist circumference (ρ = -0.21, CI = -0.24 to -0.19).

CONCLUSION

In relatively healthy middle-aged to older men, mean serum total testosterone concentration is stable with ageing, while mean SHBG concentration increases. Both total testosterone and SHBG concentrations were highly concordant over time.

Relationships Between 24-hour LH and Testosterone Concentrations and With Other Pituitary Hormones in Healthy Older Men

Objective

To investigate the relationship between LH and testosterone (T), which characteristics associate with the strength of this relationship, and their interrelationships with GH, TSH, cortisol, and ACTH.

Design

Hormones were measured in serum samples collected every 10 minutes during 24 hours from 20 healthy men, comprising 10 offspring of long-lived families and 10 control subjects, with a mean (SD) age of 65.6 (5.3) years. We performed cross-correlation analyses to assess the relative strength between 2 timeseries for all possible time shifts.

Results

Mean (95% CI) maximal correlation was 0.21 (0.10-0.31) at lag time of 60 minutes between LH and total T concentrations. Results were comparable for calculated free, bioavailable, or secretion rates of T. Men with strong LH-T cross-correlations had, compared with men with no cross-correlation, lower fat mass (18.5 [14.9-19.7] vs. 22.3 [18.4-29.4] kg), waist circumference (93.6 [5.7] vs. 103.1 [12.0] cm), high-sensitivity C-reactive protein (0.7 [0.4-1.3] vs. 1.8 [0.8-12.3] mg/L), IL-6 (0.8 [0.6-1.0] vs. 1.2 [0.9-3.0] pg/mL), and 24-hour mean LH (4.3 [2.0] vs. 6.1 [1.5] U/L), and stronger LH-T feedforward synchrony (1.5 [0.3] vs. 1.9 [0.2]). Furthermore, T was positively cross-correlated with TSH (0.32 [0.21-0.43]), cortisol (0.26 [0.19-0.33]), and ACTH (0.26 [0.19-0.32]).

Conclusions

LH is followed by T with a delay of 60 minutes in healthy older men. Men with a strong LH-T relationship had more favorable body composition, inflammatory markers, LH levels, and LH-T feedforward synchrony. We observed positive correlations between T and TSH, cortisol, and ACTH.

Concentrations of nine endogenous steroid hormones in 70-year-old men and women

OBJECTIVES

Circulating concentrations of endogenous steroids have systemic implications on health in elderly. However, population-based age- and ethnicity-specific data are scarce. The aim was to report sex-specific plasma concentrations of endogenous sex and adrenal steroids in elderly Swedish Caucasians, to examine the impact of BMI and to present concentrations in apparently healthy subjects.

METHODS

A population-based observational study of 70-year olds, including 684 community-dwelling men and women enrolled in the PIVUS study, Sweden. Median plasma concentrations were determined using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for pregnenolone, 17-hydroxypregnenolone, 17-hydroxy-progesterone, 11-deoxycortisol, DHEA, androstenedione, testosterone, estrone and estradiol.

RESULTS

Plasma concentrations were significantly higher in men (n = 452) than in women (n = 232) for estradiol: median 61.3 pmol/L (95% CI, 11.4, 142.7) vs 18.4 (4.0, 127.3), for estrone: 92.8 (33.3, 206) vs 71.6 (17.8, 209) pmol/L, and for testosterone 13.8 (5.7, 28.0) vs 0.7 (0.2, 2.0) nmol/L. Higher concentrations of estrone and estradiol were observed in obese than non-obese women. Compared to non-obese men, obese men had lower concentrations of testosterone and its precursors: 17-hydroxypregnenolone, 17-hydroxyprogesterone, androstenedione and DHEA. The subgroup of apparently healthy individuals had median values > 20% lower for estrone and estradiol in women but slightly higher for testosterone in both sexes.

CONCLUSIONS

Concentrations of estradiol, estrone and testosterone were higher in 70-year-old men than in women. BMI associated positively to estradiol and estrone in women and negatively to testosterone in men. Apparently healthy women had lower median concentrations of estradiol and estrone and men had higher median testosterone compared to all individuals.

Age-related changes in human Leydig cell status

STUDY QUESTION

What are the consequences of ageing on human Leydig cell number and hormonal function?

SUMMARY ANSWER

Leydig cell number significantly decreases in parallel with INSL3 expression and Sertoli cell number in aged men, yet the in vitro Leydig cell androgenic potential does not appear to be compromised by advancing age.

WHAT IS KNOWN ALREADY

There is extensive evidence that ageing is accompanied by decline in serum testosterone levels, a general involution of testis morphology and reduced spermatogenic function. A few studies have previously addressed single features of the human aged testis phenotype one at a time, but mostly in tissue from patients with prostate cancer.

STUDY DESIGN, SIZE, DURATION

This comprehensive study examined testis morphology, Leydig cell and Sertoli cell number, steroidogenic enzyme expression, INSL3 expression and androgen secretion by testicular fragments in vitro. The majority of these endpoints were concomitantly evaluated in the same individuals that all displayed complete spermatogenesis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Testis biopsies were obtained from 15 heart beating organ donors (age range: 19-85 years) and 24 patients (age range: 19-45 years) with complete spermatogenesis. Leydig cells and Sertoli cells were counted following identification by immunohistochemical staining of specific cell markers. Gene expression analysis of INSL3 and steroidogenic enzymes was carried out by qRT-PCR. Secretion of 17-OH-progesterone, dehydroepiandrosterone, androstenedione and testosterone by in vitro cultured testis fragments was measured by LC-MS/MS. All endpoints were analysed in relation to age.

MAIN RESULTS AND THE ROLE OF CHANCE

Increasing age was negatively associated with Leydig cell number (R = -0.49; P < 0.01) and concomitantly with the Sertoli cell population size (R= -0.55; P < 0.001). A positive correlation (R = 0.57; P < 0.001) between Sertoli cell and Leydig cell numbers was detected at all ages, indicating that somatic cell attrition is a relevant cellular manifestation of human testis status during ageing. INSL3 mRNA expression (R= -0.52; P < 0.05) changed in parallel with Leydig cell number and age. Importantly, steroidogenic capacity of Leydig cells in cultured testis tissue fragments from young and old donors did not differ. Consistently, age did not influence the mRNA expression of steroidogenic enzymes. The described changes in Leydig cell phenotype with ageing are strengthened by the fact that the different age-related effects were mostly evaluated in tissue from the same men.

LIMITATIONS, REASONS FOR CAUTION

In vitro androgen production analysis could not be correlated with in vivo hormone values of the organ donors. In addition, the number of samples was relatively small and there was scarce information about the concomitant presence of potential confounding variables.

WIDER IMPLICATIONS OF THE FINDINGS

This study provides a novel insight into the effects of ageing on human Leydig cell status. The correlation between Leydig cell number and Sertoli cell number at any age implies a connection between these two cell types, which may be of particular relevance in understanding male reproductive disorders in the elderly. However aged Leydig cells do not lose their in vitro ability to produce androgens. Our data have implications in the understanding of the physiological role and regulation of intratesticular sex steroid levels during the complex process of ageing in humans.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by grants from Prin 2010 and 2017. The authors have no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Male infertility due to testicular disorders

CONTEXT

Male infertility is defined as the inability to conceive following 1 year of regular unprotected intercourse. It is the causative factor in 50% of couples and a leading indication for assisted reproductive techniques (ART). Testicular failure is the most common cause of male infertility, yet the least studied to date.

EVIDENCE ACQUISITION

The review is an evidence-based summary of male infertility due to testicular failure with a focus on etiology, clinical assessment, and current management approaches. PubMed-searched articles and relevant clinical guidelines were reviewed in detail.

EVIDENCE SYNTHESIS/RESULTS

Spermatogenesis is under multiple levels of regulation and novel molecular diagnostic tests of sperm function (reactive oxidative species and DNA fragmentation) have since been developed, and albeit currently remain as research tools. Several genetic, environmental, and lifestyle factors provoking testicular failure have been elucidated during the last decade; nevertheless, 40% of cases are idiopathic, with novel monogenic genes linked in the etiopathogenesis. Microsurgical testicular sperm extraction (micro-TESE) and hormonal stimulation with gonadotropins, selective estrogen receptor modulators, and aromatase inhibitors are recently developed therapeutic approaches for men with the most severe form of testicular failure, nonobstructive azoospermia. However, high-quality clinical trials data is currently lacking.

CONCLUSIONS

Male infertility due to testicular failure has traditionally been viewed as unmodifiable. In the absence of effective pharmacological therapies, delivery of lifestyle advice is a potentially important treatment option. Future research efforts are needed to determine unidentified factors causative in "idiopathic" male infertility and long-term follow-up studies of babies conceived through ART.

Lowered Serum Testosterone Concentration Is Associated With Enhanced Inflammation and Worsened Lipid Profile in Men

The negative relationship between testosterone and inflammatory cytokines has been reported for decades, although the exact mechanisms of their interactions are still not clear. At the same time, little is known about the relation between androgens and acute phase proteins. Therefore, in this investigation, we aimed to study the relationship between androgen status and inflammatory acute phase reactants in a group of men using multi-linear regression analysis. Venous blood samples were taken from 149 men ranging in age from 18 to 77 years. Gonadal androgens [testosterone (T) and free testosterone (fT)], acute phase reactants [C-reactive protein (CRP), ferritin (FER), alpha-1-acid glycoprotein (AAG), and interleukin-6 (IL-6)], cortisol (C), and lipid profile concentrations were determined. It was demonstrated that the markers of T and fT were negatively correlated with all acute phase proteins (CRP, FER, and AAG; p < 0.02) and the blood lipid profile [total cholesterol (TC), low-density lipoprotein (LDL), and triglycerides (TG); p < 0.03]. Multivariate analysis showed that T, fT, and the fT/C ratio were inversely correlated with the CRP, AAG, and FER concentrations independently of age and blood lipids. When adjustment for BMI was made, T, fT, and the fT/C ratio were negatively correlated with the AAG concentrations only. In addition, it was demonstrated that gonadal androgens were positively correlated with physical activity level (p < 0.01). We have concluded that a lowered serum T concentration may promote inflammatory processes independently of adipose tissue and age through a reduced inhibition of inflammatory cytokine synthesis, which leads to enhanced acute phase protein production. Therefore, a low serum T concentration appears to be an independent risk factor in the development of atherosclerosis and cardiovascular diseases. Moreover, the positive correlation between testosterone and physical activity level suggests that exercise training attenuates the age-related decrease in gonadal androgens and, in this way, may reduce the enhancement of systemic low-grade inflammation in aging men.

Male reproductive health in cystic fibrosis

The impact of cystic fibrosis (CF) on male reproductive health is profound. The vast majority of men with CF are infertile due to obstructive azoospermia. Multiple factors associated with CF contribute to an increased prevalence of testosterone deficiency, which adversely affects muscle mass, bone density, and quality of life. This article reviews the pathophysiology, diagnosis, and management of infertility and testosterone deficiency that occur in men with CF. With improving survival of CF patients, these topics are becoming more significant in their clinical care.

Longitudinal changes in plasma sex hormone concentrations correlate with changes in CT-measured regional adiposity among Japanese American men over 10 years

OBJECTIVE

Ageing in male adults is typically accompanied by adiposity accumulation and changes in circulating sex hormone concentrations. We hypothesized that an ageing-associated increase in oestrogens and decrease in androgens would correlate with an increase in adiposity.

DESIGN

10-year prospective, observational study.

STUDY SUBJECTS

A total of 190, community-dwelling men in the Japanese American Community Diabetes Study.

MEASUREMENTS

At 0 and 10 years, CT scanning quantified intra-abdominal fat (IAF) and subcutaneous fat (SCF) areas while plasma concentrations of oestradiol, oestrone, testosterone and dihydrotestosterone were measured by liquid chromatography-tandem-mass spectrometry at each time point. Multivariate linear regression analyses assessed correlations between 10-year changes in hormone concentrations and IAF or SCF, adjusting for age and baseline fat depot area.

RESULTS

Participants were middle-aged [median 54.8 years, interquartile range (IQR) 39.9-62.8] men and mostly overweight by Asian criterion (median BMI 24.9, IQR 23.3-27.1) and with few exceptions had normal sex-steroid concentrations. Median oestradiol and dihydrotestosterone did not change significantly between 0 and 10 years (P = .084 and P = .596, respectively) while median oestrone increased (P < .001) and testosterone decreased (P < .001). Median IAF and SCF increased from 0 to 10 years (both P < .001). In multivariate analyses, change in oestrone positively correlated (P = .019) while change in testosterone (P = .003) and dihydrotestosterone (P = .014) negatively correlated with change in IAF. Plasma oestradiol and oestrone positively correlated with change in SCF (P = .041 and P = .030, respectively) while testosterone (P = .031) negatively correlated in multivariate analysis.

CONCLUSION

Among 190 community-dwelling, Japanese American men, increases in IAF were associated with decreases in plasma androgens and increases in plasma oestrone, but not oestradiol, at 10 years. Further research is necessary to understand whether changing hormone concentrations are causally related to changes in regional adiposity or whether the reverse is true.

Age-Related Male Hypogonadism and Cognitive Impairment in the Elderly: Focus on the Effects of Testosterone Replacement Therapy on Cognition

BACKGROUND

Epidemiological data report that male hypogonadism may play a role in cognitive impairment in elderly. However, the effect of testosterone replacement therapy (TRT) on cognitive abilities in this cluster of patients has not been well established. Methods. PubMed/MEDLINE, Google Scholar, Cochrane Library, and Web of Science were searched by using free text words and medical subject headings terms related with "male hypogonadism", "late-onset hypogonadism", elderly, cognition, "mild cognitive impairment", memory, "testosterone replacement therapy" used in various combinations according to the specific clinical questions. Original articles, reviews, and randomized controlled trials written in English were selected. Results. A long-term TRT could improve specific cognitive functions, such as verbal and spatial memory, cognitive flexibility, and physical vitality. However, randomized controlled trials do not provide positive results, and in most of the cases TRT might not induce beneficial effects on cognitive function in elderly men. Discussion and conclusions. Since the lengthening of life expectancy, the prevalence rate of cognitive decline in elderly men is expected to increase remarkably over the next decade with considerable healthcare and economical concerns. Therefore, this remains a relevant clinical topic and further investigations are needed for clarifying the role of TRT especially in elderly men with hypogonadism.

Testosterone for Androgen Deficiency-Like Symptoms in Men Without Pathologic Hypogonadism: A Randomized, Placebo-Controlled Cross-over With Masked Choice Extension Clinical Trial

BACKGROUND

Off-label testosterone prescribing for androgen deficiency (AD)-like sexual and energy symptoms of older men without pathologic hypogonadism has increased dramatically without convincing evidence of efficacy.

METHODS

In a randomized, double-blind, placebo-controlled study with three phases, we entered 45 men aged at least 40 years without pathologic hypogonadism but with AD-like energy and/or sexual symptoms to either daily testosterone or placebo gel treatment for 6 weeks in a cross-over study design with a third, mandatory extension phase in which participants chose which previous treatment they preferred to repeat while remaining masked to their original treatment. Primary endpoints were energy and sexual symptoms as assessed by a visual analog scale (Lead Symptom Score [LSS]).

RESULTS

Increasing serum testosterone to the healthy young male range produced no significant benefit more than placebo for energy or sexual LSS. Covariate effects of age, body mass index, and pretreatment baseline serum testosterone on quality-of-life scales were detected. Only 1 out of 22 indices from seven quality-of-life scales was significantly improved by testosterone treatment over placebo. Participants did not choose testosterone significantly more than placebo as their preferred treatment in the third phase.

CONCLUSIONS

Six-week testosterone treatment does not improve energy or sexual symptoms more than placebo in symptomatic men without pathologic hypogonadism.

Current National and International Guidelines for the Management of Male Hypogonadism: Helping Clinicians to Navigate Variation in Diagnostic Criteria and Treatment Recommendations

Male hypogonadism-rebadged by some as testosterone deficiency syndrome-is a clinical and biochemical diagnosis of increasing worldwide interest. Organic male hypogonadism-usually permanent-is well-established, but aging men may also exhibit lower serum testosterone levels; principally due to burden of extra-gonadal comorbidities such as obesity, diabetes and metabolic syndrome, but with an underlying intact hypothalamo-pituitary-testicular (HPT) axis capable of springing back into operation once comorbidities are addressed. Despite encouraging observational data and plausible theoretical underpinning, evidence for efficacy and safety of testosterone in this "aging" group of men is lacking; addressing comorbid illnesses remains the key priority instead. Nevertheless, in recent years, accumulation of misleading information online has triggered a global tsunami of testosterone prescriptions. Despite this, many men with organic hypogonadism remain undiagnosed or untreated; many more face a diagnostic odyssey before achieving care by the appropriate specialist. As testosterone therapy is not without risk several clinical practice guidelines have been published specialist societies to guide physicians on best practice. However, these are heterogeneous in key areas, reflecting divergent approaches to the same evidence basis. Herein, we navigate the major clinical practice guidelines on male hypogonadism and test their respective recommendations against current best evidence.

The role of testosterone in chronic kidney disease and kidney function in men and women: a bi-directional Mendelian randomization study in the UK Biobank

BACKGROUND

Chronic kidney disease (CKD) has an apparent sex disparity, with a more rapid progress in men than in women. Whether the well-established sex-specific evolutionary biology trade-off between reproduction and longevity might inform CKD has not previously been considered. Relevant evidence from randomized controlled trials (RCTs) is not available.

METHODS

We used a bi-directional Mendelian randomization study to obtain unconfounded estimates using the UK Biobank. Single nucleotide polymorphisms (SNPs) that strongly (p value < 5 × 10^-8) predicted testosterone in a sex-specific manner were applied to 179,916 white British men (6016 CKD cases) and 212,079 white British women (5958 CKD cases) to obtain sex-specific associations with CKD, albuminuria, and estimated glomerular filtration rate (eGFR). We also used multivariable MR to control for sex hormone binding globulin (SHBG). For validation, we similarly examined their role in hemoglobin and high-density lipoprotein cholesterol (HDL-c). We also assessed the role of kidney function in serum testosterone, by applying eGFR-related SNPs to testosterone in the UK Biobank.

RESULTS

Genetically predicted testosterone was associated with CKD in men (odds ratio (OR) for bioavailable testosterone 1.17 per standard deviation, 95% confidence interval (CI) 1.03 to 1.33) based on 125 SNPs but not in women (OR 1.02, 95% CI 0.92 to 1.14 for total testosterone) based on 254 SNPs. Multivariable MR allowing for SHBG showed consistent patterns. Genetically predicted bioavailable testosterone in men and women and genetically predicted total testosterone in women increased hemoglobin and lowered HDL-c, as seen in RCTs. Genetically predicted eGFR was not related to serum testosterone in men or in women.

CONCLUSIONS

Genetically predicted testosterone was associated with CKD and worse kidney function in men, whilst not affected by kidney function. Identifying drivers of testosterone and the underlying pathways could provide new insights into CKD prevention and treatment.

Age-Related Alterations in Endocrine Markers Do Not Match Changes in Psychosocial Measures: Findings From the Men's Health 40+ Longitudinal Study

While life expectancy continues to increase, aging can bring several distinct endocrine and psychosocial changes. The study aimed to investigate the interplay between biopsychosocial factors of healthy aging in specifically healthy aging men. Ninety-seven healthy aging men were investigated at two time points spanning 4 years. Participants completed questionnaires measuring several psychosocial dimensions and gave saliva samples for hormone quantification during a laboratory appointment. The study applied a random intercept mixed-model approach. Age-related changes were found in most endocrine markers (cortisol, testosterone, dehydroepiandrosterone-sulfate, and progesterone), except for estradiol. Psychosocial measures remained stable, except for increased social support. Further, changes in endocrine and psychosocial measures were independent of each other. The results suggest that in healthy aging men, age-related endocrine changes occur, but do not necessarily determine a change in psychosocial measures. Potentially, preventive interventions can be derived from these results.

The effects of age and obesity on postprandial dynamics of serum testosterone levels in men

OBJECTIVE

Guidelines recommend using fasting samples to evaluate testosterone (T) levels in men, as free and total T levels decrease postprandially. However, it is not clear whether these dynamics are affected by age or obesity. This could be relevant given the obesity epidemic, ageing population and the barrier for screening which fasting could impose.

DESIGN/PARTICIPANTS

A total of 43 men underwent a solid mixed meal tolerance test. Serum samples were taken fasting, and at 30, 60 and 120 minutes postprandially. A commercial immunoassay was used to determine sex hormone-binding globulin (SHBG) levels, liquid chromatography coupled to tandem mass spectroscopy for total T concentrations and free T levels were calculated.

RESULTS

Postprandially, both total and free T were lower at all-time points compared with fasting (all, P < .005). At 60 minutes, maximum mean decreases of 15 ± 15% and 17 ± 16% were seen for total and free T levels, respectively. Younger men had greater decreases in both total and free T levels compared with men older than 40 years (all, P < .05). A greater decrease at 30 and 60 minutes postprandially was observed for both total and free T levels in nonobese vs obese men (all, P < .05).

CONCLUSIONS

After a mixed meal, total and free T serum levels decreased whereas SHBG levels did not change. Interestingly, postprandial decreases were less pronounced in men older than 40 years and/or with obesity. Although this study indicates less pronounced decreases in certain men, fasting samples remain a prerequisite for establishing correct diagnosis of male hypogonadism.

Female and male serum reference intervals for challenging sex and precursor steroids by liquid chromatography - tandem mass spectrometry

Measuring some sex and precursor steroids is still challenging even by liquid chromatography - tandem mass spectrometry (LC-MS/MS), and few normal values are available. We developed a LC-MS/MS method for estradiol, estrone, dihydrotestosterone and 17-hydroxypregnenolone measurement, compared it with direct immunoassays, and generated sex, age, menopausal and menstrual status specific reference intervals. Liquid-liquid extraction was optimized on 300 μL serum spiked with isotopic internal standards. A 2D-LC system allowed on-line purification and separation in 11 min run. Electrospray ionization was enhanced by ammonium fluoride. MS-detection was obtained by multiple reaction monitoring. Direct ECLIA for estradiol (n = 80) and RIA for estrone (n = 41) were compared with LC-MS/MS. Reference values were estimated in healthy, lean women in reproductive age (n = 118), menopausal women (n = 33) and men (n = 159). The assay showed satisfying imprecision, trueness, recovery and selectivity. Adequate functional sensitivity was achieved for measuring estrone (18.1 pmol/L) and 17-hydroxypregnenolone (117 pmol/L) in all subjects, and estradiol (35.9 pmol/L) and dihydrotestosterone (134 pmol/L) in women in reproductive age and men, but not in menopausal women. Compared with LC-MS/MS, immunoassays showed good agreement for estradiol but severe disagreement for estrone. Estrogens exhibited sex, menopausal and menstrual variations. Dihydrotestosterone and 17-hydroxypregnenolone depended on sex and menopause, the latter also declining with age in men. Strictly defined reference intervals in the adult female and male population were generated for challenging steroids such as estrogens, dihydrotestosterone and 17-hydroxypregnenolone by a novel LC-MS/MS method. Our achievement can be used to deepen the comprehension of several endocrine diseases.

Testicular Aging: An Overview of Ultrastructural, Cellular, and Molecular Alterations

The trend in parenthood at an older age is increasing for both men and women in developed countries, raising concerns about the reproductive ability, and the consequences for the offspring's health. While reproductive activity in women stops with menopause, a complete cessation of the reproductive potential does not occur in men. Although several studies have been published on the effects of aging on semen parameters and spermatozoa DNA integrity, literature on impact of aging on the testis, particularly cellular, and molecular alterations, has been, so far, limited and controversial. This work discusses the current knowledge on testicular aging in humans and other mammals, covering topics from tissue ultrastructure, to cellular and molecular alterations. Aging affects male reproductive function at multiple levels, from sperm production and quality, to the morphology and histology of the male reproductive system. The morphological and functional changes that occur in the testes result in variations in the levels of many hormones, changes in molecules involved in mitochondrial function, receptors, and signaling proteins. Despite knowing that these age-related alterations occur, their real impact on male fertility and reproductive health are still far from being fully understood, highlighting that research in the field is crucial.

Male hypogonadism: a review

This article contains a systematic review of the main developments that have occurred in the area of male hypogonadism between the publication of the Endocrine Society Guidelines of 2010 and 2018 and after 2018.

Sex differences in serum steroid hormone levels during embryonic development in hen eggs

This experiment was conducted to explore the differences of serum steroid hormones with age and sex in hen eggs during incubation periods for identification of males and females. The concentrations of estrone (E1), estradiol (E2), estriol (E3), testosterone (T), androstenedione (A4), and dihydrotestosterone (DHT) in serum were measured by enzyme-linked immunosorbent assays in chicken embryos on 8, 10, 12, 14, and 16 D, respectively. During the development of chicken embryo, egg weight loss was closely related to age but no sex. However, it was found that both age and sex significantly affected hormones and had obviously more effect on androgens levels. Besides E2 and T, other steroids such as E1, A4, and DHT were also significantly correlated with sex (P < 0.05). Notably, the level of T and the ratio of T to E2 were significantly higher in males than females (P < 0.05). The ratio of E1 to E2 displayed different trends in different sexes, which increased in males but decreased in females. The distribution proportions of androgens and estrogens kept stable level during the late hatching periods of 12 to 16 D. The sex differences of steroids were more obvious at the late hatching stage through PCA. These suggested that the serum hormones differences in male and female embryos played a vital role in sexual differentiation. These findings not only provided the theoretical basis for sex determination of fertilized eggs in egg-laying hen strains, but also contributed to develop a non-invasive way to sex determination of fertilized eggs to meet the modern commercial application.

Androgen Effects on the Adrenergic System of the Vascular, Airway, and Cardiac Myocytes and Their Relevance in Pathological Processes

INTRODUCTION

Androgen signaling comprises nongenomic and genomic pathways. Nongenomic actions are not related to the binding of the androgen receptor (AR) and occur rapidly. The genomic effects implicate the binding to a cytosolic AR, leading to protein synthesis. Both events are independent of each other. Genomic effects have been associated with different pathologies such as vascular ischemia, hypertension, asthma, and cardiovascular diseases. Catecholamines play a crucial role in regulating vascular smooth muscle (VSM), airway smooth muscle (ASM), and cardiac muscle (CM) function and tone.

OBJECTIVE

The aim of this review is an updated analysis of the role of androgens in the adrenergic system of vascular, airway, and cardiac myocytes. Body. Testosterone (T) favors vasoconstriction, and its concentration fluctuation during life stages can affect the vascular tone and might contribute to the development of hypertension. In the VSM, T increases α1-adrenergic receptors (α ₁-ARs) and decreases adenylyl cyclase expression, favoring high blood pressure and hypertension. Androgens have also been associated with asthma. During puberty, girls are more susceptible to present asthma symptoms than boys because of the increment in the plasmatic concentrations of T in young men. In the ASM, β ₂-ARs are responsible for the bronchodilator effect, and T augments the expression of β ₂-ARs evoking an increase in the relaxing response to salbutamol. The levels of T are also associated with an increment in atherosclerosis and cardiovascular risk. In the CM, activation of α _1A-ARs and β ₂-ARs increases the ionotropic activity, leading to the development of contraction, and T upregulates the expression of both receptors and improves the myocardial performance.

CONCLUSIONS

Androgens play an essential role in the adrenergic system of vascular, airway, and cardiac myocytes, favoring either a state of health or disease. While the use of androgens as a therapeutic tool for treating asthma symptoms or heart disease is proposed, the vascular system is warmly affected.

Androgens are effective bronchodilators with anti-inflammatory properties: A potential alternative for asthma therapy

Changes in plasma androgen levels in asthmatic men may be linked to asthma severity, seemingly acting through nongenomic and genomic effects. Nongenomic effects include rapid relaxation of carbachol or antigenic challenge pre-contracted guinea pig airway smooth muscle (ASM) in vitro: testosterone (TES) blocks l-type voltage dependent Ca²⁺ channels, stored operated Ca²⁺ channels, inositol 1,4,5-trisphosphate receptors and promotes prostaglandin E₂ biosynthesis. In ASM at rest, TES lowers basal intracellular Ca²⁺ concentration and tension, maintaining a proper airway patency keeping steady smooth muscle tension and basal intracellular Ca²⁺ concentration at rest. Moreover, the bronchospasm in sensitized guinea-pigs was ablated by dehydroepiandrosterone (DHEA), a precursor of steroids, TES and its metabolites 5α- and 5β-dihydrotestosterone (DHT). On the other hand, genomic effects related to androgens' anti-inflammatory properties in asthma have been recently studied. Briefly, TES negatively regulates type 2 immune response sustained by CD4+ Th2 and group 2 innate lymphoid cells, diminishing allergic airway inflammation in males. Also, novel findings establish that TES decreases interleukin (IL)-17A protein expression produced by CD4+ Th17 cells and therefore neutrophilic airway inflammation. Clearly, DHEA, TES or its 5β-reduced metabolite that possesses minimal androgenic effect, might have potential therapeutic capacities in the treatment of severe asthma via mechanisms distinct from corticosteroid treatment.

Reproducibility of Acute Steroid Hormone Responses in Men to Short-Duration Running

PURPOSE

Progressively overloading the body to improve physical performance may lead to detrimental states of overreaching/overtraining syndrome. Blunted cycling-induced cortisol and testosterone concentrations have been suggested to indicate overreaching after intensified training periods. However, a running-based protocol is yet to be developed or demonstrated as reproducible. This study developed two 30-min running protocols, (1) 50/70 (based on individualized physical capacity) and (2) RPETP (self-paced), and measured the reproducibility of plasma cortisol and testosterone responses.

METHODS

Thirteen recreationally active, healthy men completed each protocol (50/70 and RPETP) on 3 occasions. Venous blood was drawn preexercise, postexercise, and 30 min postexercise.

RESULTS

Cortisol was unaffected (both P > .05; 50/70, ηp2 = .090; RPETP, ηp2 = .252), while testosterone was elevated (both P < .05; 50/70, 35%, ηp2 = .714; RPETP, 42%, ηp2 = .892) with low intraindividual coefficients of variation (CVi) as mean (SD) (50/70, 7% [5%]; RPETP, 12% [9%]). Heart rate (50/70, effect size [ES] = 0.39; RPETP, ES = -0.03), speed (RPETP, ES = -0.09), and rating of perceived exertion (50/70 ES = -0.06) were unchanged across trials (all CVi < 5%, P < .05). RPETP showed greater physiological strain (P < .01).

CONCLUSIONS

Both tests elicited reproducible physiological and testosterone responses, but RPETP induced greater testosterone changes (likely due to increased physiological strain) and could therefore be considered a more sensitive tool to potentially detect overtraining syndrome. Advantageously for the practitioner, RPETP does not require a priori exercise-intensity determination, unlike the 50/70, enhancing its integration into practice.

An Accurate Substitution Method To Minimize Left Censoring Bias in Serum Steroid Measurements

Hormone assay results below the assay detection limit (DL) can introduce bias into quantitative analysis. Although complex maximum likelihood estimation methods exist, they are not widely used, whereas simple substitution methods are often used ad hoc to replace the undetectable (UD) results with numeric values to facilitate data analysis with the full data set. However, the bias of substitution methods for steroid measurements is not reported. Using a large data set (n = 2896) of serum testosterone (T), DHT, estradiol (E2) concentrations from healthy men, we created modified data sets with increasing proportions of UD samples (≤40%) to which we applied five different substitution methods (deleting UD samples as missing and substituting UD sample with DL, DL/√2, DL/2, or 0) to calculate univariate descriptive statistics (mean, SD) or bivariate correlations. For all three steroids and for univariate as well as bivariate statistics, bias increased progressively with increasing proportion of UD samples. Bias was worst when UD samples were deleted or substituted with 0 and least when UD samples were substituted with DL/√2, whereas the other methods (DL or DL/2) displayed intermediate bias. Similar findings were replicated in randomly drawn small subsets of 25, 50, and 100. Hence, we propose that in steroid hormone data with ≤40% UD samples, substituting UD with DL/√2 is a simple, versatile, and reasonably accurate method to minimize left censoring bias, allowing for data analysis with the full data set.

Aging and the Male Reproductive System

This narrative review presents an overview of current knowledge on fertility and reproductive hormone changes in aging men, the factors driving and modulating these changes, their clinical consequences, and the benefits and risks of testosterone (T) therapy. Aging is accompanied by moderate decline of gamete quality and fertility. Population mean levels show a mild total T decline, an SHBG increase, a steeper free T decline, and a moderate LH increase with important contribution of comorbidities (e.g., obesity) to these changes. Sexual symptoms and lower hematocrit are associated with low T and are partly responsive to T therapy. The relationship of serum T with body composition and metabolic health is bidirectional; limited beneficial effects of T therapy on body composition have only marginal effects on metabolic health and physical function. Skeletal changes are associated primarily with estradiol and SHBG. Cognitive decline is not consistently linked to low T and is not improved by T therapy. Although limited evidence links moderate androgen decline with depressive symptoms, T therapy has small beneficial effects on mood, depressive symptoms, and vitality in elderly patients with low T. Suboptimal T (and/or DHT) has been associated with increased risk of stroke, but not of ischemic heart disease, whereas an association with mortality probably reflects that low T is a marker of poor health. Globally, neither severity of clinical consequences attributable to low T nor the nature and magnitude of beneficial treatment effects justify the concept of some broadly applied "T replacement therapy" in older men with low T. Moreover, long-term safety of T therapy is not established.

Abaloparatide improves cortical geometry and trabecular microarchitecture and increases vertebral and femoral neck strength in a rat model of male osteoporosis

Androgen deficiency is a leading cause of male osteoporosis, with bone loss driven by an inadequate level of bone formation relative to the extent of bone resorption. Abaloparatide, an osteoanabolic PTH receptor agonist used to treat women with postmenopausal osteoporosis at high risk for fracture, increases bone formation and bone strength in estrogen-deficient animals without increasing bone resorption. This study examined the effects of abaloparatide on bone formation, bone mass, and bone strength in androgen-deficient orchiectomized (ORX) rats, a male osteoporosis model. Four-month-old Sprague-Dawley rats underwent ORX or sham surgery. Eight weeks later, sham-operated rats received vehicle (saline; n = 10) while ORX rats (n = 10/group) received vehicle (Veh) or abaloparatide at 5 or 25 μg/kg (ABL5 or ABL25) by daily s.c. injection for 8 weeks, followed by sacrifice. Dynamic bone histomorphometry indicated that the tibial diaphysis of one or both abaloparatide groups had higher periosteal mineralizing surface, intracortical bone formation rate (BFR), endocortical BFR, and cortical thickness vs Veh controls. Vertebral trabecular BFR was also higher in both abaloparatide groups vs Veh, and the ABL25 group had higher trabecular osteoblast surface without increased osteoclast surface. By micro-CT, the vertebra and distal femur of both abaloparatide-groups had improved trabecular bone volume and micro-architecture, and the femur diaphysis of the ABL25 group had greater cortical thickness with no increase in porosity vs Veh. Biomechanical testing indicated that both abaloparatide-groups had stronger vertebrae and femoral necks vs Veh controls. These findings provide preclinical support for evaluating abaloparatide as an investigational treatment for male osteoporosis.

Steroid secretion in healthy aging

Nowadays, people spend a considerable amount of their lives as older adults, but this longer lifespan is often accompanied by an increase in chronic conditions and disease, resulting in reduced quality of life and unprecedented societal and economic burden. Healthy aging is therefore increasingly recognized as a healthcare priority. Physical and mental adaptations to changes over the life course, and the maintenance of well-being, represent pivotal challenges in healthy aging. To capture the complexity of healthy aging, we propose a specific phenotype based on body composition, cognition, mood, and sexual function as indicators of different dimensions of healthy aging. With increasing age, sex hormones as well as glucocorticoids undergo significant alterations, and different patterns emerge for women and men. This review describes age-related patterns of change for women and men, and sheds light on the underlying mechanisms. Furthermore, an overview is provided of the challenges for healthy aging resulting from these age-related steroid alterations. While clinical practice guidelines recommend hormonal treatment only in the case of consistently low hormone levels and symptoms of hormone deficiency, physical exercise and a healthy lifestyle emerge as preventive strategies which can counter age-related hormonal changes and at best prevent chronic conditions.

Role of Hypothalamic-Pituitary-Adrenal Axis, Hypothalamic-Pituitary-Gonadal Axis and Insulin Signaling in the Pathophysiology of Alzheimer's Disease

Alzheimer's disease (AD), the commonest progressive neurodegenerative disorder of the brain, is clinically characterized by the formation of extracellular amyloid plaques and intracellular neurofibrillary tangles. Recent studies suggest a relationship between the endocrinal dysregulation and the neuronal loss during the AD pathology. Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis and hypothalamic-pituitary-gonadal (HPG) axis regulating circulating levels of glucocorticoid hormones has been implicated in the pathophysiology of AD. Likewise, dysregulated insulin signaling, impaired glucose uptake and insulin resistance are some of the prime factors in the onset/progression of AD. In this review, we have discussed the changes in HPA and HPG axes, implicated insulin resistance/signaling and glucose regulation during the onset/progression of AD. Therefore, simultaneous detection of these endocrinal markers in the early or presymptomatic stages may help in the early diagnosis of AD. This evidence for implicated endocrinal functions supports the fact that modulation of endocrinal pathways can be used as therapeutic targets for AD. Future studies need to determine how the induction or inhibition of endocrinal targets could be used for predictable neuroprotection in AD therapies.

PITUITARY EVALUATION IN PATIENTS WITH LOW PROSTATE-SPECIFIC ANTIGEN

OBJECTIVE

To evaluate pituitary function in men with a low screening prostate-specific antigen (PSA) of ≤0.1 ng/mL and test the hypothesis that low PSA is associated with hypogonadism alone or other hormone deficiency.

METHODS

This was a case-control study evaluating the rates of hypogonadism and low insulin-like growth factor (IGF)-1 in a cohort of men with low or normal screening PSA level. Sixty-four men >40 years old without known prostate disease were divided into a low-PSA group (PSA ≤0.1 ng/mL) and normal-PSA group (PSA 1 to 4 ng/mL). Hormonal evaluation included total testosterone, prolactin, luteinizing hormone, follicle-stimulating hormone, IGF-1, growth hormone, thyroid-stimulating hormone, free thyroxine, morning cortisol, and adrenocorticotropic hormone. The difference between each patient's observed IGF-1 and the IGF-1 age-specific lower limit was calculated. The odds ratios (ORs) for having hypogonadism and associated 95% confidence intervals (CIs) were calculated using the Cochran-Mantel-Haenszel test.

RESULTS

The rate of hypogonadism was significantly higher in the low-PSA group (n = 44) compared with the normal-PSA control group (n = 20) (45.5% vs. 15.0%; OR, 4.7; 95% CI, 1.2 to 18.4; P = .027). The total testosterone in the low-PSA group was significantly lower compared with the control group (181.7 ng/dL vs. 263.7 ng/dL; P = .008). IGF-1 values were below their lower bound in 18.6% of subjects in the low-PSA group, compared with 0% in the control group.

CONCLUSION

Men with low PSA have significantly higher rates of hypogonadism and low IGF-1 compared with those with normal PSA. In such men, we recommend hormonal evaluation to exclude associated pituitary dysfunction.

ABBREVIATIONS

BMI = body mass index; GH = growth hormone; IGF-1 = insulin-like growth factor 1; MRI = magnetic resonance imaging; PSA = prostate-specific antigen; T2DM = type 2 diabetes mellitus; VA-NWIHCS = VA-Nebraska Western Iowa Health Care System.