Lowered testosterone in male obesity: mechanisms, morbidity and management

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.

Cardiac disease is linked to adiposity in male gorillas (Gorilla gorilla gorilla)

Cardiac disease is a major cause of morbidity and mortality for adult gorillas. Previous research indicates a sex-based difference with predominantly males demonstrating evidence of left ventricular hypertrophy. To evaluate these findings, we analyzed serum markers with cardiac measures in a large sample of gorillas. The study sample included 44 male and 25 female gorillas housed at American Association of Zoo and Aquariums (AZA)-accredited zoos. Serum samples were collected from fasted gorillas during routine veterinary health exams and analyzed to measure leptin, adiponectin, IGF-1, insulin, ferritin, glucose, triglycerides, and cholesterol. Cardiac ultrasonography via transthoracic echocardiogram was performed simultaneously. Three echocardiographic parameters were chosen to assess cardiac disease according to parameters established for captive lowland gorillas: left ventricular internal diameter, inter-ventricular septum thickness, and left ventricular posterior wall thickness. Our data revealed that high leptin, low adiponectin, and lowered cholesterol were significantly and positively correlated with measures of heart thickness and age in males but not in females. Lowered cholesterol in this population would be categorized as elevated in humans. High leptin and low adiponectin are indicative of increased adiposity and suggests a potential parallel with human obesity and cardiovascular disease in males. Interestingly, while females exhibited increased adiposity with age, they did not progress to cardiac disease.

Testosterone therapy to prevent type 2 diabetes mellitus in at-risk men (T4DM): Design and implementation of a double-blind randomized controlled trial

BACKGROUND

Low circulating testosterone is associated with an increased risk of developing type 2 diabetes (T2DM) in overweight men with impaired glucose tolerance (IGT).

AIMS

To determine in a multi-centre, double-blinded placebo-controlled randomized trial whether testosterone treatment combined with lifestyle intervention (Weight Watchers) relative to lifestyle intervention alone reduces T2DM incidence and improves glucose tolerance at 2 years.

STUDY POPULATION

Overweight or obese men aged 50-74 years with a serum testosterone of ≤14 nmol/L and IGT or newly diagnosed T2DM established by an oral glucose tolerance test (OGTT).

SETTING, DRUG AND PROTOCOL

Six Australian capital city-based tertiary care centres. Participants were randomized 1:1 and injected with testosterone undecanoate (1000 mg/4 mL) or vehicle (4 mL castor oil), at baseline, 6 weeks and 3-monthly thereafter. PRIMARY ENDPOINTS: (a) Proportion of participants with 2-hour OGTT ≥11.1 mmol/L at 2 years, and (b) a difference at 2 years ≥0.6 mmol/L in the mean 2-hour OGTT glucose between treatments.

SECONDARY ENDPOINTS

Fasting insulin, HbA1c, body composition, maximal handgrip strength; sexual function and lower urinary tract symptoms; serum sex steroids and sex hormone binding globulin; mood and psychosocial function; adherence to lifestyle intervention; and healthcare utilization and costs.

SAFETY

Overseen by an Independent Data Safety Monitoring Committee. Haematocrit, lipids and prostate-specific antigen (PSA) are assessed 6-monthly and information relating to haematological, urological and cardiovascular adverse events from each clinic visit. SUB-STUDIES: (a) Changes in bone density and micro-architecture, (b) motivation and behaviour, (c) telomere length, (d) extended treatment up to 4 years, and (e) hypothalamo-pituitary testicular axis recovery at treatment end.

Influence of season, tourist activities and camp management on body condition, testicular and adrenal steroids, lipid profiles, and metabolic status in captive Asian elephant bulls in Thailand

We previously found relationships between body condition and physiological function affecting health and welfare of female tourist camp elephants in Thailand, and used that approach to conduct a similar study of bull elephants in the same camps (n = 13). A body condition score (BCS) was done every other month, and fecal glucocorticoid metabolite (FGM) concentrations were measured twice monthly for 1 year. Effects of season, camp management and tourist activity on lipid profiles [total cholesterol (TC), low density lipoproteins (LDL), high density lipoproteins (HDL), triglycerides (TG)] and metabolic factors [insulin, glucose, fructosamine, glucose to insulin ratio (G:I)] were determined and correlated to measures of body condition, testosterone and FGM. Positive correlations were found between BCS and TG, between FGM and TG, HDL and glucose, and between testosterone and HDL, whereas BCS and testosterone were negatively associated with the G:I. There was a significant positive relationship between FGM and testosterone. Elevated FGM concentrations were associated with altered lipid and metabolic profiles and were higher in winter compared to summer and rainy seasons. Insulin and glucose levels were higher, while the G:I was lowest in the winter season. Strong positive associations were found between TC and HDL, LDL and HDL and glucose, and glucose and insulin. By contrast, negative relationships were found between the G:I and HDL and glucose, and between insulin and G:I. Differences also were found between High and Low tourist season months for FGM, insulin, and G:I. Last, there was notable variation among the camps in measured parameters, which together with tourist season effects suggests camp management may affect physiological function and welfare; some negatively like feeding high calorie treats, others positively, like exercise. Last, compared to females, bull elephants appear to be in better physical health based on normal BCSs, lower insulin levels and higher G:I ratios.

On the Abilities of Unconscious Freudian Motivational Drives to Evoke Conscious Emotions

Human beings use conscious emotions to direct their behaviors. There is some agreement in the scientific community that unconscious motivations are able to evoke conscious emotions. This manuscript focuses on Freudian motivational drives as inductors for unconscious motivation, and also on Panksepp's framework of affective neuroscience for describing the generation of emotions. Recently, it has been suggested that imperative motor factors of Freudian drives (i.e., the hormones ghrelin, testosterone, angiotensin II and adenosine) have the ability to activate both a drive-specific brain area and brain areas of the SEEKING command system. In fact, this manuscript contends that all imperative motor factors have typical SEEKING targets (i.e., so-called receptors) in the brain areas of both nucleus accumbens and lateral hypothalamus. In addition, all imperative motor factors are able to target the central amygdala directly, a brain area classified by Panksepp as the instinctual part of the FEAR command system. Another point of interest may be the evaluation that imperative motor factors of the sexual drive, hunger and thirst can directly activate the RAGE command system by targeting the medial amygdala. Surprisingly, all imperative motor factors are able to modulate Panksepp's granddaddy mechanism, i.e., to stimulate all seven command systems via the lateral hypothalamus. Orexinergic neurons exclusively located in the lateral hypothalamus have targets for imperative motor factors and project axons to characteristic brain areas of all seven command systems. From the fact that the imperative motor factors of the sexual drive and hunger act in an excitatory manner on orexinergic neurons whereas those of thirst and sleep inhibit such neurons, temporary termination of hunger by thirst may be understood as a very simple example of a co-regulation of Freudian drives. The author wishes to note that there are motivational drives other than the ones described by Freud. Bowlby was obviously the first in describing such drives, and Bowlbyian drive activities cannot be explained with the intermediacy of imperative motor factors. Nevertheless, the ignorance of the magnificent importance of imperative motor factors must be discarded.

A Short Study Exploring the Effect of the Glycaemic Index of the Diet on Energy intake and Salivary Steroid Hormones

Background: The glycaemic index or load (GI or GL) is a concept for ranking carbohydrate-rich foods based on the postprandial blood glucose response compared with a reference food (glucose). Due to the limited research investigating the effect of the GI or GL of the diet on salivary steroidal hormones, this explorative short study was conducted. Methods: 12 female participants consumed a low GI and a high GI diet for three days each, followed by a washout period between each intervention. Saliva was collected at baseline, and following the low or high GI diets. Cortisol and testosterone concentrations were measured by enzyme-linked immuno-sorbent assay (ELISA). Results: GI and GL were significantly different between the low and high GI diets (p < 0.001). There was a small but significant increase in salivary cortisol after the high GI diet (7.38 to 10.93 ng/mL, p = 0.036). No effect was observed after the low GI diet. Higher levels of testosterone were produced after the low GI diet (83.7 to 125.9 pg/mL, p = 0.002), and no effect was found after the high GI diet. The total intake of calories consumed on the low GI diet was significantly lower compared to the high GI diet (p = 0.019). Conclusions: A low GI diet was associated with a small but significant increase in salivary testosterone, while a high GI diet increased cortisol levels. Altering the GI of the diet may influence overall energy intake and the health and wellbeing of female volunteers.

Effects of aging, high-fat diet, and testosterone treatment on neural and metabolic outcomes in male brown Norway rats

Risk for Alzheimer's disease (AD) is affected by multiple factors, including aging, obesity, and low testosterone. We previously showed that obesity and low testosterone independently and interactively exacerbate AD-related outcomes in young adult rodents. The goals of the present study are two-fold: to examine whether the effects of an obesogenic diet differ with increasing age and to determine if testosterone treatment in middle-aged and aged animals mitigates negative effects of the diet. Male brown Norway rats were maintained on control or high-fat diets for 12 weeks beginning in young adulthood, middle age, or advanced age. Separate cohorts of middle-aged and aged animals were treated with testosterone during dietary manipulations. Endpoints included metabolic indices, inflammation, cognitive performance, and neural health outcomes. Aging was associated with poorer outcomes that were generally exacerbated by high-fat diet, especially at middle age. Testosterone treatment was largely without benefit, exerting only subtle effects on a select number of measures. Understanding how the deleterious effects of obesity are affected by advancing age and the ability of protective strategies such as testosterone to reduce these effects may provide significant insight into both the development and prevention of age-related cognitive decline and AD.

Long-term follow-up of gonadal dysfunction in morbidly obese adolescent boys after bariatric surgery

Background Elevated body mass index (BMI) is associated with hypogonadism in men but this is not well described in adolescents. The aim is to evaluate gonadal dysfunction and the effects of weight loss after gastric banding in obese adolescent boys. Methods Thirty-seven of 54 boys (age 16.2±1.2 years, mean BMI 48.2 kg/m2) enrolled at the Center for Adolescent Bariatric Surgery at Columbia University Medical Center had low total testosterone for Tanner 5 <350 ng/dL. Sixteen had long-term hormonal data for analysis at baseline (T0), 1 year (T1) and 2 years (T2) post-surgery. T-tests, chi-squared (χ2) tests, correlation and linear mixed models were performed. Results At T0, the hypogonadal group had higher systolic blood pressure (SBP) (75th vs. 57th percentile, p=0.02), fasting insulin (19 vs. 9 μIU/mL, p=0.0008) and homeostatic index of insulin resistance (HOMA-IR) (4.2 vs. 1.9, p=0.009) compared to control group. Total testosterone was negatively correlated with fasting insulin and HOMA-IR. In the long-term analysis, BMI, weight, waist circumference (WC), and % excess weight decreased at T1 and T2 compared to T0. Mean total testosterone at T0, T1 and T2 were 268, 304 and 368 ng/dL, respectively (p=0.07). There was a statistically significant negative correlation between BMI and testosterone after 2 years (r=-0.81, p=0.003). Conclusions Low testosterone levels but unaltered gonadotropins are common in this group and associated with insulin resistance. While a significant increase in testosterone was not found over time, the negative relationship between BMI and testosterone persisted, suggesting there may be an optimal threshold for testosterone production with respect to BMI. Long-term studies are needed.

Testosterone-Associated Dietary Pattern Predicts Low Testosterone Levels and Hypogonadism

Obesity and low serum testosterone (T) levels are interrelated and strongly influenced by dietary factors, and their alteration entails a great risk of hypogonadism. Substantial evidence suggests a bidirectional relationship between nutrient metabolism (e.g., glucose, lipids, and iron) and T levels in men; however, T-related dietary patterns remain unclear. This study investigated the dietary patterns associated with serum total T levels and its predictive effect on hypogonadism and the body composition. Anthropometry, blood biochemistry, and food frequency questionnaires were collected for 125 adult men. Dietary patterns were derived using a reduced rank regression from 32 food groups. Overall prevalence rates of central obesity and hypogonadism were 48.0% and 15.7%, respectively. An adjusted linear regression showed that age, insulin, red blood cell (RBC) aggregation, and transferrin saturation independently predicted serum total T levels (all p < 0.01). The total T-related dietary pattern (a high consumption of bread and pastries, dairy products, and desserts, eating out, and a low intake of homemade foods, noodles, and dark green vegetables) independently predicted hypogonadism (odds ratio: 5.72; 95% confidence interval: 1.11‒29.51, p < 0.05) for those with the highest dietary pattern scores (Q4) compared to those with the lowest (Q1). Scores were also negatively correlated with the skeletal muscle mass (p for trend = 0.002) but positively correlated with the total body fat mass (p for trend = 0.002), visceral fat mass (p for trend = 0.001), and to a lesser extent, subcutaneous fat mass (p for trend = 0.035) after adjusting for age. Randomized controlled trials are needed to confirm that improvement in dietary pattern can improve T levels and reduce hypogonadism.

Downregulation of leptin receptor and kisspeptin/GPR54 in the murine hypothalamus contributes to male hypogonadism caused by high-fat diet-induced obesity

PURPOSE

Obesity may lead to male hypogonadism, the underlying mechanism of which remains unclear. In the present study, we established a murine model of male hypogonadism caused by high-fat diet-induced obesity to verify the following hypotheses: 1) an increased leptin level may be related to decreased secretion of GnRH in obese males, and 2) repression of kisspeptin/GPR54 in the hypothalamus, which is associated with increased leptin levels, may account for the decreased secretion of GnRH and be involved in secondary hypogonadism (SH) in obese males.

METHODS

Male mice were fed high-fat diet for 19 weeks and divided by body weight gain into diet-induced obesity (DIO) and diet-induced obesity resistant (DIO-R) group. The effect of obesity on the reproductive organs in male mice was observed by measuring sperm count and spermatozoid motility, relative to testis and epididymis weight, testosterone levels, and pathologic changes. Leptin, testosterone, estrogen, and LH in serum were detected by ELISA method. Leptin receptor (Ob-R), Kiss1, GPR54, and GnRH mRNA were measured by real-time PCR in the hypothalamus. Expression of kisspeptin and Ob-R protein was determined by Western blotting. Expression of GnRH and GPR54 protein was determined by immunohistochemical analysis.

RESULTS

We found that diet-induced obesity decreased spermatozoid motility, testis and epididymis relative coefficients, and plasma testosterone and luteinizing hormone levels. An increased number and volume of lipid droplets in Leydig cells were observed in the DIO group compared to the control group. Significantly, higher serum leptin levels were found in the DIO and DIO-R groups. The DIO and DIO-R groups showed significant downregulation of the GnRH, Kiss1, GPR54, and Ob-R genes. We also found decreased levels of GnRH, kisspeptin, GPR54, and Ob-R protein in the DIO and DIO-R groups.

CONCLUSIONS

These lines of evidence suggest that downregulation of Ob-R and kisspeptin/GPR54 in the murine hypothalamus may contribute to male hypogonadism caused by high-fat diet-induced obesity.

Potential application of testosterone replacement therapy as treatment for obesity and type 2 diabetes in men

Sedentary lifestyle and over-nutrition are the main causes of obesity and type 2 diabetes (T2D). However, the same causes are major triggers of hypogonadism. Many T2D patients show low testosterone levels while hypogonadal men seem to be prone to become diabetic. Testosterone plays a major role in the regulation of muscle mass, adipose tissue, inflammation and insulin sensitivity and is therefore indirectly regulating several metabolic pathways, while T2D is commonly triggered by insulin resistance, increased adipose tissue and inflammation, showing a negative correlation between testosterone levels and T2D. Testosterone replacement therapy (TRT) is widely used in patients with symptoms of hypogonadism, however it is not commonly used as preventive intervention or treatment for T2D patients even though hypogonadal patients share many common symptoms (obesity, insulin insensitivity, increased inflammation, decrease in muscle mass and strength) with T2D patients. Even though TRT is often associated with side effects such as prostatic hypertrophy or cancer, cardiovascular risks due to increase in the number of red blood cells and infertility, several studies have shown that TRT remains a potent intervention improving metabolic functions such as glycated haemoglobin, blood sugar, total cholesterol and visceral fat. The purpose of this review is to discuss the possible benefits and risks of TRT in the prevention and treatment of obesity and T2D and assess the health risks and benefits of common T2D medications and testosterone.

Circulating Testosterone as the Hormonal Basis of Sex Differences in Athletic Performance

Elite athletic competitions have separate male and female events due to men's physical advantages in strength, speed, and endurance so that a protected female category with objective entry criteria is required. Prior to puberty, there is no sex difference in circulating testosterone concentrations or athletic performance, but from puberty onward a clear sex difference in athletic performance emerges as circulating testosterone concentrations rise in men because testes produce 30 times more testosterone than before puberty with circulating testosterone exceeding 15-fold that of women at any age. There is a wide sex difference in circulating testosterone concentrations and a reproducible dose-response relationship between circulating testosterone and muscle mass and strength as well as circulating hemoglobin in both men and women. These dichotomies largely account for the sex differences in muscle mass and strength and circulating hemoglobin levels that result in at least an 8% to 12% ergogenic advantage in men. Suppression of elevated circulating testosterone of hyperandrogenic athletes results in negative effects on performance, which are reversed when suppression ceases. Based on the nonoverlapping, bimodal distribution of circulating testosterone concentration (measured by liquid chromatography-mass spectrometry)-and making an allowance for women with mild hyperandrogenism, notably women with polycystic ovary syndrome (who are overrepresented in elite athletics)-the appropriate eligibility criterion for female athletic events should be a circulating testosterone of <5.0 nmol/L. This would include all women other than those with untreated hyperandrogenic disorders of sexual development and noncompliant male-to-female transgender as well as testosterone-treated female-to-male transgender or androgen dopers.

Inverse association of testosterone and sex hormone binding globulin levels with leukocyte count in middle-aged and elderly men

OBJECTIVE

The inverse associations of testosterone and sex hormone-binding globulin (SHBG) levels with cardiometabolic diseases are well established and are increasingly viewed as inflammatory diseases. This study aimed to examine the associations of testosterone and SHBG levels with leukocyte count in 451 Korean men aged ≥50 years.

METHODS

Serum testosterone and SHBG levels were categorized into tertiles. High leukocyte count was defined as ≥7340 cells/μl, which corresponded to the 75th percentile of the current sample. The odds ratios (ORs) and 95% confidence intervals (95% CIs) for high leukocyte count were calculated across testosterone and SHBG tertiles using multiple logistic regression analysis.

RESULTS

The mean leukocyte counts significantly decreased with increasing testosterone and SHBG tertiles. The ORs (95% CIs) of high leukocyte count for the first tertile of testosterone and SHBG were 3.27 (1.34-7.95) and 2.38 (1.05-5.96), respectively, compared with the referent third tertile, after adjusting for age, smoking status, alcohol drinking, regular exercise, body mass index, blood pressure, fasting plasma glucose, triglyceride, and high-density lipoprotein (HDL) cholesterol level.

CONCLUSION

We found inversely graded associations of low testosterone and SHBG levels with leukocyte count. These findings suggest that low testosterone and SHBG levels may be interpreted as a state of low-grade inflammation.

Role of estrogen receptors, P450 aromatase, PCNA and p53 in high-fat-induced impairment of spermatogenesis in rats

Obesity and overweight are frequently associated with male subfertility. To address new findings on the players involved in the obesity-induced impairment of spermatogenesis, we used a high-fat diet-induced overweight-rat model. Following four weeks of high-fat diet, the organization of seminiferous epithelium was affected, and tubules lumen showed immature/degenerated cells, typical signs of hormonal imbalance and testicular damage. Real-time PCR analysis allowed us to detect increased levels of ERα and decreased levels of aromatase CYP19 transcripts in testis, suggesting an increase in circulating estrogens derived from the accumulating adipose tissue rather than the induction of testicular estrogen synthesis. Moreover, in situ hybridization analysis showed an increased susceptibility towards estrogens in testis from high-fat fed rats, being ERs expressed not only in spermatogonia, as in control testis, but also in spermatids. Western blot and immunohistochemical analyses revealed an increase in the amount of p53 and PCNA, together with a change in their immunodetection, being the proteins localised on germ cells at different stages of maturation. Differences in p53 and PCNA expression may give evidence and be part of a cellular response to stress conditions and damage caused by the excessive intake of saturated fatty acids.

Gender and Sex Differences in Adipose Tissue

PURPOSE OF REVIEW

As the ongoing epidemic of adult and childhood obesity grows, it puts a greater burden on individuals and the healthcare system due to increased prevalence of obesity-associated diseases. An important area that has gained much attention recently is the sex and gender difference related to obesity and associated complications. Basic science and clinical studies have now improved our understanding of obesity and have discovered adipose tissue biology to be key in metabolism.

RECENT FINDINGS

There is evidence related to the sex dichotomy in obesity in a variety of areas including adipocyte function, sex hormone effects, genetics, and metabolic inflammation leading to critical differences in adipose tissue biology. The sex and gender difference in adipose tissue is a factor that should be considered when studying an individuals' risk for obesity and metabolic dysfunction. This understanding is important for strategizing treatment and prevention measures.

Hypogonadism and male obesity: Focus on unresolved questions

Obesity, increasing in prevalence globally, is the clinical condition most strongly associated with lowered testosterone concentrations in men and presents as one of the strongest predictors of receiving testosterone treatment. While low circulating total testosterone concentrations in modest obesity primarily reflect reduced concentrations of sex hormone binding globulin, more marked obesity can lead to genuine hypothalamic-pituitary-testicular axis (HPT) suppression. HPT axis suppression is likely mediated via pro-inflammatory cytokine and dysregulated leptin signalling and aggravated by associated comorbidities. Whether oestradiol-mediated negative hypothalamic-pituitary feedback plays a pathogenic role requires further study. Although the obesity-hypogonadism relationship is bidirectional, the effects of obesity on testosterone concentrations are more substantial than the effects of testosterone on adiposity. In markedly obese men submitted to bariatric surgery, substantial weight loss is very effective in reactivating the HPT axis. In contrast, lifestyle measures are less effective in reducing weight and generally only associated with modest increases in circulating testosterone. In randomized controlled clinical trials (RCTs), testosterone treatment does not reduce body weight, but modestly reduces fat mass and increases muscle mass. Short-term studies have shown that testosterone treatment in carefully selected obese men may have modest benefits on symptoms of androgen deficiency and body composition even additive to diet alone. However, longer term, larger RCTs designed for patient-important outcomes and potential risks are required. Until such trials are available, testosterone treatment cannot be routinely recommended for men with obesity-associated nonclassical hypogonadism. Lifestyle measures or where indicated bariatric surgery to achieve weight loss, and optimization of comorbidities remain first line.

Androgens induce growth of the limb skeletal muscles in a rapamycin-insensitive manner

Signaling through the mechanistic target of rapamycin complex 1 (mTORC1) has been well defined as an androgen-sensitive transducer mediating skeletal muscle growth in vitro; however, this has yet to be tested in vivo. As such, male mice were subjected to either sham or castration surgery and allowed to recover for 7 wk to induce atrophy of skeletal muscle. Then, castrated mice were implanted with either a control pellet or a pellet that administered rapamycin (~2.5 mg·kg^-1·day^-1). Seven days postimplant, a subset of castrated mice with control pellets and all castrated mice with rapamycin pellets were given once weekly injections of nandrolone decanoate (ND) to induce muscle growth over a six-week period. Effective blockade of mTORC1 by rapamycin was noted in the skeletal muscle by the inability of insulin to induce phosphorylation of ribosomal S6 kinase 1 70 kDa (Thr389) and uncoordinated-like kinase 1 (Ser⁷⁵⁷). While castration reduced tibialis anterior (TA) mass, muscle fiber cross-sectional area, and total protein content, ND administration restored these measures to sham levels in a rapamycin-insensitive manner. Similar findings were also observed in the plantaris and soleus, suggesting this rapamycin-insensitive effect was not specific to the TA or fiber type. Androgen-mediated growth was not due to changes in translational capacity. Despite these findings in the limb skeletal muscle, rapamycin completely prevented the ND-mediated growth of the heart. In all, these data indicate that mTORC1 has a limited role in the androgen-mediated growth of the limb skeletal muscle; however, mTORC1 was necessary for androgen-mediated growth of heart muscle.

Obesity impairs male fertility through long-term effects on spermatogenesis

Objective

This study aimed to investigate the effect and possible underlying mechanisms of high-fat diet-induced obesity on spermatogenesis in male rats.

Methods

A total of 45 male rats were randomly divided into control (n = 15, normal diet) and obesity groups (n = 30, high-fat diet) and were fed for 16 weeks. Body weight and organ indexes were determined after sacrifice. Indicators of reproductive function, including sperm count, sperm motility, apoptosis of spermatogenic cells, and oxidative stress levels, were measured. Serum metabolic parameters and reproductive hormones were also assayed.

Results

Compared with the control group, epididymal sperm motility in the obese rats was significantly decreased (P < 0.01). Morphological analysis of the obesity group showed vacuolar changes in seminiferous tubules, spermatogenic cell dysfunction, and increased apoptosis of spermatogenic cells in testicular tissue (P < 0.05). The calculated free testosterone (cFT) concentration in serum was decreased (P < 0.05), whereas the serum sex hormone-binding globulin (SHBG) level was significantly increased (P < 0.01). The superoxide dismutase (SOD) concentration decreased and the malondialdehyde (MDA) concentration increased in testis tissues; however, neither changes were statistically significant (P > 0.05).

Results

Nutritional obesity can damage spermatogenesis in male rats due to long-term effects on spermatogenesis.

On the Drive Specificity of Freudian Drives for the Generation of SEEKING Activities: The Importance of the Underestimated Imperative Motor Factor

Doubters of Freud's theory of drives frequently mentioned that his approach is outdated and therefore cannot be useful for solving current problems in patients with mental disorders. At present, many scientists believe that affects rather than drives are of utmost importance for the emotional life and the theoretical framework of affective neuroscience, developed by Panksepp, strongly underpinned this view. Panksepp evaluated seven so-called command systems and the SEEKING system is therein of central importance. Panksepp used Pankseppian drives as inputs for the SEEKING system but noted the missing explanation of drive-specific generation of SEEKING activities in his description. Drive specificity requires dual action of the drive: the activation of a drive-specific brain area and the release of the neurotransmitter dopamine. Noticeably, as Freud claimed drive specificity too, it was here analyzed whether a Freudian drive can evoke the generation of drive-specific SEEKING activities. Special importance was addressed to the imperative motor factor in Freud's drive theory because Panksepp's formulations focused on neural pathways without specifying underlying neurotransmitter/endocrine factors impelling motor activity. As Panksepp claimed sleep as a Pankseppian drive, we firstly had to classified sleep as a Freudian drive by using three evaluated criteria for a Freudian drive. After that it was possible to identify the imperative motor factors of hunger, thirst, sex, and sleep. Most importantly, all of these imperative motor factors can both activate a drive-specific brain area and release dopamine from dopaminergic neurons, i.e., they can achieve the so-called drive specificity. Surprisingly, an impaired Freudian drive can alter via endocrinological pathways the concentration of the imperative motor factor of a second Freudian drive, obviously in some independence to the level of the metabolic deficit, thereby offering the possibility to modulate the generation of SEEKING activities of this second Freudian drive. This novel possibility might help to refine the general understanding of the action of Freudian drives. As only imperative motor factors of Freudian drives can guarantee drive specificity for the generation of SEEKING activities, the impact of Freud's construct Eros (with its constituents hunger, thirst, sex, and sleep) should be revisited.

Fish Oil Ameliorates High-Fat Diet Induced Male Mouse Reproductive Dysfunction via Modifying the Rhythmic Expression of Testosterone Synthesis Related Genes

The present study aims to investigate the protective effects of ω-3 polyunsaturated fatty acids (ω-3PUFAs) against high-fat diet induced male mouse reproductive dysfunction and to explore circadian regulation mechanisms. Male C57BL/6 mice were randomly divided into three groups and fed a normal chow diet (control group, CON), a high-fat diet (HFD group) or a HFD supplemented with fish oil (FO group) for 12 weeks. After 12 weeks of feeding, the body weight and the ratio of perinephric and epididymal fat weight to body weight were significantly higher in the HFD group compared with the CON group. The supplement of fish oil rich in ω-3PUFAs only slightly reduced the HFD-induced obesity but remarkably ameliorated HFD-induced dyslipidemia, sexual hormones disorder, testicle lesions and germ cell apoptosis. Fish oil supplementation restored the expression of steroid synthesis associated genes in HFD fed mouse and flattened the HFD-induced oscillations in circadian genes’ expression. Fish oil supplementation prevented HFD-induced male mouse reproductive dysfunction and modified the rhythmic expression of testosterone synthesis related genes.

Testosterone Deprivation Aggravates Left-Ventricular Dysfunction in Male Obese Insulin-Resistant Rats via Impairing Cardiac Mitochondrial Function and Dynamics Proteins

BACKGROUND

We have previously reported that testosterone deprivation at a very young age accelerated, but did not aggravate, left-ventricular (LV) dysfunction in obese insulin-resistant rats. However, the effects of testosterone deprivation during adulthood on LV function in obese insulin-resistant rats remains unclear. We hypothesized that testosterone deprivation aggravates LV dysfunction and cardiac autonomic imbalance via the impairment of cardiac mitochondrial function and dynamics proteins, a reduction in insulin receptor function, and an increase in apoptosis in obese insulin-resistant rats.

METHODS

Male rats were fed on either a normal diet (ND) or a high-fat diet (HFD) for 12 weeks. They were then subdivided into 2 groups: sham operation (NDS, HFS) and orchiectomy (NDO, HFO). Metabolic parameters, blood pressure, heart rate variability (HRV), and LV function were determined at baseline and before and after orchiectomy. Mitochondrial function and dynamics proteins, insulin signaling, and apoptosis were determined 12 weeks postoperatively.

RESULTS

HFS rats exhibited obese insulin resistance, depressed HRV, and LV dysfunction. In HFO rats, systolic blood pressure was increased with more excessive depression of HRV and increased LV dysfunction, compared with HFS rats. These adverse cardiac effects were consistent with markedly increased mitochondrial dysfunction, reduced mitochondrial complex I and III proteins, reduced mitochondrial fusion proteins, and increased apoptosis, compared with HFS rats. However, testosterone deprivation did not lead to any alteration in the insulin-resistant condition in HFO rats, compared with HFS rats.

CONCLUSION

We concluded that testosterone deprivation during adulthood aggravated the impairment of mitochondrial function, mitochondrial respiratory complex, mitochondrial dynamics proteins, and apoptosis, leading to LV dysfunction in obese insulin-resistant rats.

The association between serum testosterone and mortality among elderly men on hemodialysis

OBJECTIVES

This study examines the associations between total testosterone levels and dialysis mortality.

METHODS

Elderly men who initiate hemodialysis in Taoyuan General Hospital from January 2012 to June 2017 were enrolled. We reviewed clinical characteristics and biochemical data from start of dialysis and followed over a 5-year period after dialysis. Body composition parameters were assessed 3-6 months after dialysis. Skeletal muscle mass index (SMMI) was defined by skeletal muscle mass divided by squared height. We defined those with lowest tertile of testosterone values as low testosterone group. Adjusted hazard ratios (aHRs) and 95% confidence interval (95% CI) for mortality and cumulative survival curves were evaluated by Cox hazards model and Kaplan-Meier method. The discriminative power of SMMI and testosterone levels was calculated according to the area under the curve and the receiver operating characteristic curve (AUROC).

RESULTS

From a total of 137 elderly hemodialysis patients, the range of lowest, middle, and highest tertile of testosterone values was <6.25 nmol/L, 6.25-10.5 nmol/L, and >10.5 nmol/L. After multivariate adjustment other than SMMI, total testosterone levels at baseline were a significant predictor for mortality aHR(95% CI): 0.79 (0.70-0.91). The unadjusted and adjusted c-statistics of SMMI vs testosterone values to predict overall were 770 (0.688-0.852) vs 0.779 (0.691-0.866) and 855 (0.812-0.886) vs 0.812 (0.744-0.856) (Ps < .05), whereas the capacity of c-statistics was similar (χ²  = 0.143 and 2.709, Ps > .05).

CONCLUSIONS

Total testosterone value was a predictor for mortality. It was noninferior to SMMI in predicting dialysis mortality.

Korean red ginseng (Panax ginseng) inhibits obesity and improves lipid metabolism in high fat diet-fed castrated mice

ETHNOPHARMACOLOGICAL RELEVANCE

Korean red ginseng (Panax ginseng C.A. Meyer, Araliaceae) has been historically used as a traditional drug for the prevention and treatment of most ageing-related diseases, such as obesity, dyslipidemia, diabetes, and cardiovascular disease. Elderly men with testosterone deficiency are strongly associated with many of the aforementioned metabolic diseases. The aim of this study was to determine the effects of ginseng on obesity and lipid metabolism in a mouse model of testosterone deficiency (castrated C57BL/6J mice).

MATERIALS AND METHODS

The effects of ginseng extract (GE) on obesity and lipid metabolism in high-fat diet (HFD)-fed castrated C57BL/6J mice were examined using hematoxylin and eosin staining, serum lipid analysis, and quantitative real-time polymerase chain reaction (PCR). The effects of GE, ginsenosides, and testosterone on adipogenesis were measured using Oil Red O staining, XTT assay, and real-time PCR.

RESULTS

Compared with HFD mice, mice receiving HFD supplemented with GE (HFD-GE) for 8 weeks showed decreased body weight, adipose tissue mass, and adipocyte size without affecting food intake. Serum levels of triglycerides and total cholesterol were lowered in HFD-GE mice than in HFD mice. GE also markedly reduced HFD-induced hepatic lipid accumulation. Concomitantly, HFD-GE decreased mRNA expression of adipogenesis-related genes (SREBP-1C, PPARγ, FAS, SCD1, and ACC1) in visceral adipose tissues compared with HFD alone. Consistent with the in vivo data, GE and major active ginsenosides (Rb1 and Rg1) decreased lipid accumulation and mRNA expression of PPARγ, C/EBPα, and SCD1 in 3T3-L1 adipocytes compared with control. Similarly, testosterone also decreased lipid accumulation and mRNA levels of PPARγ, C/EBPα, and SCD1. These inhibitory effects were further increased by co-treatment of GE or ginsenosides with testosterone.

CONCLUSIONS

Our results demonstrate that ginseng can inhibit obesity and dyslipidemia in HFD-fed castrated mice, possibly by inhibiting adipogenic gene expression. In addition, our results indicate that ginseng may act like testosterone to inhibit adipogenesis, suggesting that ginseng may be able to prevent obesity, hyperlipidemia, and hepatic steatosis in men with testosterone deficiency.

Relationships between total testicular volume, reproductive parameters and surrogate measures of adiposity in men presenting for couple's infertility

The objective of this study was to investigate the relationships between total testicular volume (TTV), reproductive parameters and adiposity measures: body mass index, waist circumference and waist-to-height ratio. Semen analysis was performed, and reproductive hormone levels were measured in 2,672 male patients (mean age 32.6) due to couple's infertility. Significant, positive correlations between semen parameters and the TTV were found. Gonadotrophins were negatively related to the TTV, and testosterone was not related to the TTV. Three anthropometric parameters were negatively correlated to the total sperm count, and sperm concentration seen in men with a TTV of ≤46 ml. In the case of a TTV >46 ml, only the semen volume was inversely correlated with WC and WHtR. These changes occurred from a WHtR ≥0.56, WC ≥102 cm and BMI ≥29 and were more pronounced between WHtR and the TTV. Adiposity was associated with a significant testosterone level decline but did not have a major impact on the gonadotrophin levels. This study shows the divergent results in sperm parameters in different TTV groups in the presence of central adiposity.

Cross-sectional association between testosterone, sex hormone-binding globulin and metabolic syndrome: The Healthy Twin Study

OBJECTIVES

This study evaluated an association between testosterone, sex hormone-binding globulin (SHBG) and metabolic syndrome (MetS).We also evaluated the genetic and environmental influences on the association.

DESIGN

Cross-sectional.

SETTING

Community-based study.

PARTICIPANTS

A total of 1098 Korean adult men including 139 monozygotic twin pairs.

MAIN OUTCOME MEASURE

MetS was defined using the National Cholesterol Education Program-Third Adult Treatment Panel (NCEP ATP III) and International Diabetes Federation (IDF) criteria. The associations between MetS and sex hormones were evaluated using linear mixed model and generalized estimating equation model.

RESULTS

After considering covariates such as smoking, alcohol consumption and physical exercises as well as SHBG or testosterone, the risk of MetS defined by NCEP ATP III criteria decreased by 31%, 29%, and 48%, respectively, with 1-standard deviation increase in total testosterone (TT), free testosterone (cFT) and SHBG. Similar findings were revealed with IDF criteria. Metabolic component specific analysis showed that sex hormones were inversely associated with several components of MetS: TT with abdominal obesity, low high-density lipoprotein cholesterol (HDL-C) and high blood pressure; cFT with abdominal obesity and high blood pressure; SHBG with all components except high blood pressure. Cotwin control analysis found an inverse correlation between within-pair differences in testosterone and SHBG levels and within-pair differences in waist circumference only.

CONCLUSION

Both testosterone and SHBG were inversely associated with MetS although the inverse associations with the sex hormones were not consistently found across individual metabolic components. Findings from cotwin analysis suggest a significant contribution of unshared unique environmental effect to the association between testosterone and SHBG and abdominal obesity.

Effect of ageing and single nucleotide polymorphisms associated with the risk of aggressive prostate cancer in a New Zealand population

Prostate cancer is one of the most significant male health concerns worldwide, and various researchers carrying out molecular diagnostics have indicated that genetic interactions with biological and behavioral factors play an important role in the overall risk and prognosis of this disease. Single nucleotide polymorphisms are increasingly becoming strong biomarker candidates to identify the susceptibility of individuals to prostate cancer. We carried out risk association of different stages of prostate cancer to a number of single nucleotide polymorphisms to identify the susceptible alleles in a New Zealand population and checked the interaction with environmental factors as well. We identified a number of single nucleotide polymorphisms to have associations specifically to the risk of prostate cancer and aggressiveness of the disease, and also certain single nucleotide polymorphisms to be vulnerable to the reported behavioral factors. We have addressed "special" environmental conditions prevalent in New Zealand, which can be used as a model for a bigger worldwide study.

The difference in expression of long noncoding RNAs in rat semen induced by high-fat diet was associated with metabolic pathways

Background

Obesity, a common metabolic disease, is a known cause of male infertility due to its associated health risk. Long noncoding RNAs (lncRNAs) have also been reported to be associated with male reproductive diseases; however, their role in the association between high-fat diet-induced obesity (DIO) and male reproduction remains unclear.

Methods

We used microarray analysis to compare the expression levels of lncRNAs and mRNAs in the spermatozoa of rats with DIO and normal rats. We selected a few lncRNAs that were obviously up-regulated or down-regulated, and then used RT-PCR to verify the accuracy of their expression. We then performed a functional enrichment analysis of the differentially expressed mRNAs using gene ontology and pathway analysis. Finally, target gene predictive analysis was used to explore the relationship between lncRNAs and mRNAs.

Results

The results revealed a statistically significant difference in the fasting blood glucose level in rats with DIO and control rats. We found that 973 lncRNAs and 2,994 mRNAs were differentially expressed in the sperm samples of the DIO rats, compared to the controls. GO enrichment analysis revealed 263 biological process terms, 39 cellular component terms, and 40 molecular function terms (p < 0.01) in the differentially expressed mRNAs. The pathway analysis showed that metabolic pathways were most enriched in protein-coding genes.

Discussion

To the best of our knowledge, this is the first report to show differences in the expression levels of lncRNAs and mRNAs in the sperms of rats with DIO and normal rats, and to determine the expression profile of lncRNAs in the sperm of rats with DIO. Our results have revealed a number of lncRNAs and pathways associated with obesity-induced infertility, including metabolic pathways. These pathways could be new candidates that help cope with and investigate the mechanisms behind the progression of obesity-induced male infertility.

Diet-induced obesity impairs spermatogenesis: a potential role for autophagy

Autophagy is an evolutionarily conserved process that plays a crucial role in maintaining a series of cellular functions. It has been found that autophagy is closely involved in the physiological process of spermatogenesis and the regulation of sperm survival and motility. However, the role of autophagy in high-fat diet (HFD)-induced impaired spermatogenesis remains unknown. This study was designed to investigate the role of autophagy in HFD-induced spermatogenesis deficiency and employed chloroquine (CQ) to inhibit autophagy and rapamycin (RAP) to induce autophagy. 3-methyladenine (3-MA) and CQ were administered via intratesticular injection in vivo. The effects of CQ and 3-MA on the parameters of spermatozoa co-cultured with palmitic acid (PA) in vitro were also investigated. Human semen samples from obese, subfertile male patients were also collected to examine the level of autophagy. The results suggested that HFD mice subjected to CQ showed improved spermatogenesis. Inhibiting autophagy with CQ improved the decreased fertility of HFD male mice. Moreover, the in vivo and in vitro results indicated that both CQ and 3-MA could suppress the pathological changes in spermatozoa caused by HFD or PA treatment. Additionally, the excessive activation of autophagy was also observed in sperm samples from obese, subfertile male patients.

Who Gets Testosterone? Patient Characteristics Associated with Testosterone Prescribing in the Veteran Affairs System: a Cross-Sectional Study

BACKGROUND

There has been concern about the growing off-label use of testosterone. Understanding the context within which testosterone is prescribed may contribute to interventions to improve prescribing.

OBJECTIVE

To evaluate patient characteristics associated with receipt of testosterone.

DESIGN

Cross-sectional.

SETTING

A national cohort of male patients, who had received at least one outpatient prescription within the Veterans Affairs (VA) system during Fiscal Year 2008- Fiscal Year 2012.

PARTICIPANTS

The study sample consisted of 682,915 non-HIV male patients, of whom 132,764 had received testosterone and a random 10% sample, 550,151, had not.

MAIN MEASURES

Conditions and medications associated with testosterone prescription.

KEY RESULTS

Only 6.3% of men who received testosterone from the VA during the study period had a disorder of the testis, pituitary or hypothalamus associated with male hypogonadism. Among patients without a diagnosed disorder of hypogonadism, the use of opioids and obesity were the strongest predictors of testosterone prescription. Patients receiving >100 mg/equivalents of oral morphine daily (adjusted odds ratio = 5.75, p < 0.001) and those with body mass index (BMI) >40 kg/m² (adjusted odds ratio = 3.01, p < 0.001) were more likely to receive testosterone than non-opioid users and men with BMI <25 kg/m². Certain demographics (age 40-54, White race), comorbid conditions (sleep apnea, depression, and diabetes), and medications (antidepressants, systemic corticosteroids) also predicted a higher likelihood of testosterone receipt, all with an adjusted odds ratio less than 2 (p < 0.001).

CONCLUSIONS

In the VA, 93.7% of men receiving testosterone did not have a diagnosed condition of the testes, pituitary, or hypothalamus. The strongest predictors of testosterone receipt (e.g., obesity, receipt of opioids), which though are associated with unapproved, off-label use, may be valid reasons for therapy. Interventions should aim to increase the proportion of testosterone recipients who have a valid indication.

Interaction of sex steroid hormones and obesity on insulin resistance and type 2 diabetes in men: the Third National Health and Nutrition Examination Survey

AIMS

We examined interaction of sex steroid hormones and obesity with regard to insulin resistance (IR) and type 2 diabetes (T2D) by using nationally representative data from the US.

METHODS

Data of 1461 men aged ≥20years who participated in the Third National Health and Nutrition Examination Survey were analyzed. Multiplicative interaction was calculated by cross-product interaction terms in multivariable logistic regression models. Additive interaction was assessed by the relative excess risk due to interaction (RERI).

RESULTS

After adjusting for demographic and lifestyle covariates, the odds of IR were greatest among obese men with low free testosterone and high androstanediol glucuronide. Multiplicative interactions for total testosterone, free testosterone, and free estradiol index (FEI) were statistically significant with central obesity but not with overweight and obesity regarding to T2D (P<0.05). Significant additive interactions with obesity or central obesity were detected for total testosterone (RERI=2.75, 95% CI=0.92,4.59), SHBG (RERI=5.71, 95% CI=0.77,10.64), and FEI (RERI=-9.96, 95% CI=-19.18,-0.74) with regard to IR, beta-cell dysfunction, and T2D.

CONCLUSIONS

Our findings add to the evidence suggesting that low testosterone and high estradiol may be associated greater risks of IR and T2D by interacting with overall and central obesity in adult men.

Symptomatic response to testosterone treatment in dieting obese men with low testosterone levels in a randomized, placebo-controlled clinical trial

BACKGROUND

Obese men commonly have reductions in circulating testosterone and report symptoms consistent with androgen deficiency. We hypothesized that testosterone treatment improves constitutional and sexual symptoms over and above the effects of weight loss alone.

METHODS

We conducted a pre-specified analysis of a randomized double-blind, placebo-controlled trial at a tertiary referral center. About 100 obese men (body mass index (BMI)⩾30 kg m^-2) with a repeated total testosterone level ⩽12 nmol l^-1 and a median age of 53 years (interquartile range 47-60) receiving 10 weeks of a very-low-energy diet (VLED) followed by 46 weeks of weight maintenance were randomly assigned at baseline to 56 weeks of intramuscular testosterone undecanoate (n=49, cases) or matching placebo (n=51, controls). Pre-specified outcomes were the between-group differences in Aging Male Symptoms scale (AMS) and international index of erectile function (IIEF-5) questionnaires.

RESULTS

Eighty-two men completed the study. At study end, cases showed significant symptomatic improvement in AMS score, compared with controls, and improvement was more marked in men with more severe baseline symptoms (mean adjusted difference (MAD) per unit of change in AMS score -0.34 (95% confidence interval (CI) -0.65, -0.02), P=0.04). This corresponds to improvements of 11% and 20% from baseline scores of 40 and 60, respectively, with higher scores denoting more severe symptoms. Men with erectile dysfunction (IIEF-5⩽20) had improved erectile function with testosterone treatment. Cases and controls lost the same weight after VLED (testosterone -12.0 kg; placebo -13.5 kg, P=0.40) and maintained this at study end (testosterone -11.4 kg; placebo -10.9 kg, P=0.80). The improvement in AMS following VLED was not different between the groups (-0.05 (95% CI -0.28, 0.17), P=0.65).

CONCLUSIONS

In otherwise healthy obese men with mild to moderate symptoms and modest reductions in testosterone levels, testosterone treatment improved androgen deficiency symptoms over and above the improvement associated with weight loss alone, and more severely symptomatic men achieved a greater benefit.

Interactions between inflammation, sex steroids, and Alzheimer's disease risk factors

Alzheimer's disease (AD) is an age-related neurodegenerative disorder for which there are no effective strategies to prevent or slow its progression. Because AD is multifactorial, recent research has focused on understanding interactions among the numerous risk factors and mechanisms underlying the disease. One mechanism through which several risk factors may be acting is inflammation. AD is characterized by chronic inflammation that is observed before clinical onset of dementia. Several genetic and environmental risk factors for AD increase inflammation, including apolipoprotein E4, obesity, and air pollution. Additionally, sex steroid hormones appear to contribute to AD risk, with age-related losses of estrogens in women and androgens in men associated with increased risk. Importantly, sex steroid hormones have anti-inflammatory actions and can interact with several other AD risk factors. This review examines the individual and interactive roles of inflammation and sex steroid hormones in AD, as well as their relationships with the AD risk factors apolipoprotein E4, obesity, and air pollution.

Curcumin ameliorates high‑fat diet‑induced spermatogenesis dysfunction

Curcumin, a type of natural active ingredient, is derived from rhizoma of Curcuma, which possesses antioxidant, antitumorigenic and anti-inflammatory activities. The present study aimed to investigate whether treatment with curcumin reduced high-fat diet (HFD)-induced spermatogenesis dysfunction. Sprague-Dawley rats fed a HFD were treated with or without curcumin for 8 weeks. The testis/body weight, histological analysis and serum hormone levels were used to evaluate the effects of curcumin treatment on spermatogenesis dysfunction induced by the HFD. In addition, the expression levels of apoptosis associated proteins, Fas, B-cell lymphoma (Bcl)-xl, Bcl-associated X protein (Bax) and cleaved-caspase 3, were determined in the testis. The results of the present study suggested that curcumin treatment attenuated decreased testis/body weight and abnormal hormone levels. Morphological changes induced by a HFD were characterized as atrophied seminiferous tubules, decreased spermatogenetic cells and interstitial cells were improved by curcumin treatment. In addition, curcumin treatment reduced apoptosis in the testis, and decreased expression of Fas, Bax and cleaved-caspase 3, as well as increased expression of Bcl-xl. In conclusion, the present study revealed that curcumin treatment reduced HFD-induced spermatogenesis dysfunction in male rats.

Obesity and Hypogonadism

The relationship between obesity and hypogonadism is complicated. The relationship is bidirectional and there are numerous causative and correlative factors on both sides of the equation. Obesity is increasing in prevalence in epidemic proportions. Likewise, we are beginning to see the rapid increase in the incidence of male hypogonadism. It is only recently that we are learning the ways in which these 2 conditions exacerbate each other, and we are only beginning to understand how by treating one of these conditions, we can help to treat the other as well.

Obesity and sex interact in the regulation of Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder, for which a number of genetic, environmental, and lifestyle risk factors have been identified. A significant modifiable risk factor is obesity in mid-life. Interestingly, both obesity and AD exhibit sex differences and are regulated by sex steroid hormones. Accumulating evidence suggests interactions between obesity and sex in regulation of AD risk, although the pathways underlying this relationship are unclear. Inflammation and the E4 allele of apolipoprotein E have been identified as independent risk factors for AD and both interact with obesity and sex steroid hormones. We review the individual and cooperative effects of obesity and sex on development of AD and examine the potential contributions of apolipoprotein E, inflammation, and their interactions to this relationship.

Serum 25-hydroxyvitamin D levels and testosterone deficiency in middle-aged Korean men: a cross-sectional study

Previous studies have demonstrated that male hypogonadism is associated with a low level of vitamin D. However, no reports have investigated the effects of vitamin D on testosterone levels in Korean men. Our aim was to investigate whether testosterone levels are associated with serum vitamin D levels and whether seasonal variation exists. This cross-sectional study analyzed serum 25-hydroxyvitamin D [25(OH)D], total testosterone (TT), and free testosterone (FT) in 652 Korean men over 40 years of age who had undergone a comprehensive medical examination. The average age of the subjects was 56.7 ± 7.9 years, and the mean serum 25(OH)D, TT and FT levels were 21.23 ± 7.9 ng ml⁻¹, 4.70 ± 1.6 ng ml⁻¹, and 8.12 ± 3.3 pg ml⁻¹, respectively. In the multiple linear regression model, 25(OH)D showed positive association with TT (β =0.137, P < 0.001) and FT (β =0.103, P = 0.008). 25(OH)D and FT showed similar seasonal or monthly variation after adjustment for age. A vitamin D deficiency [25(OH)D < 20 ng ml⁻¹] was associated with an increased risk of deficiencies of TT (<2.30 ng ml⁻¹) (odds ratio [OR]: 2.65; 95% confidence interval [CI]: 1.21–5.78, P = 0.014) and FT (<6.50 pg ml⁻¹) (OR: 1.44; 95% CI: 1.01–2.06 P = 0.048) after adjusting for age, season, body mass index, body composition, chronic disease, smoking, and alcohol use. In conclusion, we demonstrated a positive correlation between 25(OH)D and testosterone, which showed similar seasonal variation in Korean men.

The rs5934505 single nucleotide polymorphism (SNP) is associated with low testosterone and late-onset hypogonadism, but the rs10822184 SNP is associated with overweight and obesity in a Chinese Han population: a case-control study

Low testosterone is associated with late-onset hypogonadism (LOH) and obesity. Recently, studies have shown that four single nucleotide polymorphisms (SNPs), rs12150660, rs727428, rs5934505, and rs10822184, are associated with testosterone levels in populations of European descent. Therefore, we investigated whether the SNP loci are related to low testosterone, LOH, or obesity in a Chinese Han population. Ruling out co-morbidities, DNA was prepared from 409 men (aged 40-65 years) with low serum testosterone (defined as total testosterone <11.6 nmol/L) and 1 : 1 normal controls (matched age, body mass index (BMI), and the same living area) who were selected from 6898 males. According to the same standards, 310 men with LOH and 1 : 1 normal controls were selected from 6898 males. Excluding the cases with an unreliable sequencing result, genetic analyses were performed. The minor allele frequencies of the SNP loci rs12150660, rs727428, rs5934505, and rs10822184 were 0.1%, 44.6%, 18.7%, and 38.9%, respectively. rs5934505 was associated with the serum total testosterone and calculated free testosterone (CFT) levels (p = 0.045 and p = 0.021). rs5934505 (C>T) was associated with an increased risk of low total testosterone, low CFT, and LOH and adjusted for other factors, with an odds ratio (OR) of 2.01 (1.34-3.01), 2.14 (1.42-3.20), and 1.64 (1.04-2.58). rs10822184 was significantly correlated with weight and BMI (p = 0.035 and p = 0.027). rs10822184 (T>C) was associated with an increased risk of overweight and obesity. We adjusted for other factors, with odds ratios (ORs) of 1.94 (1.36-2.78) and 1.56 (1.00-2.43). In summary, our study provided convincing evidence that rs5934505 (C>T) was associated with the risk of low testosterone and LOH in Chinese populations. We were the first to find that rs10822184 (T>C) was significantly correlated with the risk of overweight and obesity in Chinese populations. However, further large and functional studies are warranted to confirm our findings.

The practical management of testosterone deficiency in men

Despite increased global interest in testosterone deficiency in men and its treatment with testosterone therapy, practical aspects of care remain confusing to many practitioners. Testosterone deficiency can result from testicular dysfunction (primary hypogonadism) or hypothalamic-pituitary dysfunction (secondary hypogonadism), and be congenital or acquired. Sexual and nonsexual symptoms of testosterone deficiency can negatively affect quality of life and cause considerable general health concerns. Investigation of testosterone deficiency should be undertaken in men with symptoms of reduced libido, erectile dysfunction, depression, fatigue, poor concentration, and poor memory. Total and free testosterone are the most frequently used tests and evaluating serum concentrations of luteinizing hormone aids determination of primary versus secondary testosterone deficiency. Multiple formulations of testosterone therapy are available, but symptomatic benefits might not manifest for several weeks to many months; long-acting formulations are convenient and improve compliance. Concerns regarding cardiovascular and prostate cancer risks are not supported by current evidence, monitoring during therapy is mandatory. On balance, testosterone therapy can be considered a safe and effective treatment for testosterone deficiency.

The complex and multifactorial relationship between testosterone deficiency (TD), obesity and vascular disease

Testosterone deficiency (TD) is a well-established and recognized medical condition that contributes to several co-morbidities, including metabolic syndrome, visceral obesity and cardiovascular disease (CVD). More importantly, obesity is thought to contribute to TD. This complex bidirectional interplay between TD and obesity promotes a vicious cycle, which further contributes to the adverse effects of TD and obesity and may increase the risk of CVD. Testosterone (T) therapy for men with TD has been shown to be safe and effective in ameliorating the components of the metabolic syndrome (Met S) and in contributiong to increased lean body mass and reduced fat mass and therefore contributes to weight loss. We believe that appropriate T therapy in obese men with TD is a novel medical approach to manage obesity in men with TD. Indeed, other measures of lifestyle and behavioral changes can be used to augment but not fully replace this effective therapeutic approach. It should be noted that concerns regarding the safety of T therapy remain widely unsubstantiated and considerable evidence exists supporting the benefits of T therapy. Thus, it is paramount that clinicians managing obese men with TD be made aware of this novel approach to treatment of obesity. In this review, we discuss the relationship between TD and obesity and highlight the contemporary advancement in management of obesity with pharmacological and surgical approaches, as well as utilization of T therapy and how this intervention may evolve as a novel approach to treatment of obesity in men with TD .

Testosterone deficiency, insulin-resistant obesity and cognitive function

Testosterone is an androgenic steroid hormone, which plays an important role in the regulation of male reproduction and behaviors, as well as in the maintenance of insulin sensitivity. Several studies showed that testosterone exerted beneficial effects in brain function, including preventing neuronal cell death, balancing brain oxidative stress and antioxidant activity, improving synaptic plasticity and involving cognitive formation. Although previous studies showed that testosterone deficiency is positively correlated with cognitive impairment and insulin-resistant obesity, several studies demonstrated contradictory findings. Thus, this review comprehensively summarizes the current evidence from in vitro, in vivo and clinical studies of the relationship between testosterone deficiency and insulin-resistant obesity as well as the correlation between either insulin-resistant obesity or testosterone deficiency and cognitive impairment. Controversial reports and the mechanistic insights regarding the roles of testosterone in insulin-resistant obesity and cognitive function are also presented and discussed.

Obesity and male breast cancer: provocative parallels?

While rare compared to female breast cancer the incidence of male breast cancer (MBC) has increased in the last few decades. Without comprehensive epidemiological studies, the explanation for the increased incidence of MBC can only be speculated. Nevertheless, one of the most worrying global public health issues is the exponential rise in the number of overweight and obese people, especially in the developed world. Although obesity is not considered an established risk factor for MBC, studies have shown increased incidence among obese individuals. With this observation in mind, this article highlights the correlation between the increased incidence of MBC and the current trends in obesity as a growing problem in the 21(st) century, including how this may impact treatment. With MBC becoming more prominent we put forward the notion that, not only is obesity a risk factor for MBC, but that increasing obesity trends are a contributing factor to its increased incidence.

Poor levels of agreement between serum and saliva testosterone measurement following exercise training in aging men

Testosterone (T) is a biologically important androgen that demonstrates a widely-known natural decline with advancing age. The use of salivary T (sal-T), as a determinant of systemic T, has shown promising results in recent years. However, the strength of the salivary-serum T relationship may be affected by measurement method and binding capacity with salivary proteins. The potential influence exercise may impact on this relationship is unstudied in aging men. Therefore, the aim of the present investigation was to examine the relationship of the delta change (Δ) in sal-T with Δserum T following six weeks exercise training. Fifteen sedentary (SED) males (aged 60.4 ± 5.0 years of age) and 20 lifelong exercising (LE) males (60.4 ± 4.7 years of age) were participated. Pearson's correlation coefficient revealed sal-T did not correlate with total testosterone (TT), sex hormone binding globulin (SHBG), bioactive T (bio-T), or free T (free-T) at week 0 or week 6. Δsal-T did not correlate with ΔTT, ΔSHBG, Δbio-T or Δfree-T (r = 0.271, p = 0.180; r = 0.197, p = 0.335; r = 0.258, p = 0.205; and r = 0.257, p = 0.205, respectively). In conclusion, poor levels of agreement existed between saliva and serum measurements of T in response to exercise amongst aging men.