Effects of liraglutide on obesity-associated functional hypogonadism in men

Hypogonadism and nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD), recently proposed to be renamed to metabolic dysfunction-associated steatotic liver disease (MASLD), is a major global public health concern, affecting approximately 25-30% of the adult population and possibly leading to cirrhosis, hepatocellular carcinoma, and liver transplantation. The liver is involved in the actions of sex steroids via their hepatic metabolism and production of the sex hormone-binding globulin (SHBG). Liver disease, including NAFLD, is associated with reproductive dysfunction in men and women, and the prevalence of NAFLD in patients with hypogonadism is considerable. A wide spectrum of possible pathophysiological mechanisms linking NAFLD and male/female hypogonadism has been investigated. As therapies targeting NAFLD may impact hypogonadism in men and women, and vice versa, treatments of the latter may affect NAFLD, and an insight into their pathophysiological pathways is imperative. This paper aims to elucidate the complex association between NAFLD and hypogonadism in men and women and discuss the therapeutic options and their impact on both conditions.

Obesity and sexual health: focus on postmenopausal women

Menopause is a cardiometabolic transition with many women experiencing weight gain and redistribution of body fat. Hormonal changes may affect also several dimensions of well-being, including sexual function, with a high rate of female sexual dysfunction (FSD), which displays a multifactorial etiology. The most important biological factors range from chronic low-grade inflammation, associated with hypertrophic adipocytes that may translate into endothelial dysfunction and compromised blood flow through the genitourinary system, to insulin resistance and other neuroendocrine mechanisms targeting the sexual response. Psychosocial factors include poor body image, mood disorders, low self-esteem and life satisfaction, as well as partner's health and quality of relationship, and social stigma. Even unhealthy lifestyle, chronic conditions and putative weight-promoting medications may play a role. The aim of the present narrative review is to update and summarize the state of the art on the link between obesity and FSD in postmenopausal women, pointing to the paucity of high-quality studies and the need for further research with validated end points to assess both biomarkers of obesity and FSD. In addition, we provide general information on the diagnosis and treatment of FSD at menopause with a focus on dietary interventions, physical activity, anti-obesity drugs and bariatric surgery.

Advances in the treatment of functional male hypogonadism

INTRODUCTION

Functional hypogonadism is frequently found in obese men, particularly those with metabolic complications. Several possible therapeutic approaches could be considered.

AREAS COVERED

An extensive search on Medline, Embase, and Cochrane databases was performed to retrieve the available studies assessing the change of testosterone (T) and sexual function upon dieting or physical activity programs, as well as glucagon-like peptide 1 analogues. The role of lifestyle interventions associated with T replacement therapy (TRT) was also evaluated. The expert opinion provided here has been corroborated by meta-analyzing the results of the retrieved studies.

EXPERT OPINION

Current evidence supports the beneficial role of lifestyle modifications in increasing T and improving sexual function as a function of weight loss. While dieting programs are associated with greater effects in younger populations, physical exercise has major effects in older ones. Among the dieting programs, a very low-calorie ketogenic diet shows the best results; aerobic or endurance physical exercise perform similarly. The advantages of functional hypogonadism in lifestyle modifications are empowered by the association with TRT. Therefore, TRT may be a valuable complementary strategy to increase muscle mass and facilitate physical exercise while improving sexual symptoms, thus favoring the motivation and compliance for lifestyle interventions.

Infertility Improvement after Medical Weight Loss in Women and Men: A Review of the Literature

Infertility is a modern health problem. Obesity is another expanding health issue associated with chronic diseases among which infertility is also included. This review will focus on the effects of weight loss by medical therapy on fertility regarding reproductive hormonal profile, ovulation rates, time to pregnancy, implantation rates, pregnancy rates, normal embryo development, and live birth rates. We comprised medicine already used for weight loss, such as orlistat and metformin, and emerging medical treatments, such as Glucagon-Like Peptide-1 receptor agonists (GLP-1 RA). Their use is not recommended during a planned pregnancy, and they should be discontinued in such cases. The main outcomes of this literature review are the following: modest weight loss after medication and the duration of the treatment are important factors for fertility improvement. The fecundity outcomes upon which medical-induced weight loss provides significant results are the female reproductive hormonal profile, menstrual cyclicity, ovulation and conception rates, and pregnancy rates. Regarding the male reproductive system, the fertility outcomes that feature significant alterations after medically induced weight loss are as follows: the male reproductive hormonal profile, sperm motility, movement and morphology, weight of reproductive organs, and sexual function. The newer promising GLP-1 RAs show expectations regarding fertility improvement, as they have evidenced encouraging effects on improving ovulation rates and regulating the menstrual cycle. However, more human studies are needed to confirm this. Future research should aim to provide answers about whether medical weight loss therapies affect fertility indirectly through weight loss or by a possible direct action on the reproductive system.

Impact of GLP-1 Agonists on Male Reproductive Health-A Narrative Review

Background and objective-Obesity is a prevalent health concern that notably impairs male fertility through hormonal disruptions and other pathophysiological alterations. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) can significantly reduce weight. This narrative review synthesizes the existing literature discussing the impact of glucagon-like peptide-GLP-1 RAs on the male reproductive system, particularly on the hypothalamic-pituitary-gonadal axis and spermatogenesis, highlighting their potential impact on male fertility. Material and methods-PubMed database was used for the retrieval of English-language articles published up to November 2023. This non-systematic literature review predominantly concentrates on both pre-clinical and clinical studies pertaining to GLP-1 RAs, specifically exploring their impact on male reproductive hormones and sperm parameters. Results-GLP-1 receptors have been identified within the male reproductive system according to the existing literature. While the exact mechanisms are not well understood, they appear to be involved in glucose homeostasis and energy metabolism, both vital processes in spermatogenesis. Multiple clinical trials have demonstrated the efficacy of GLP-1 RAs for promoting weight loss. Recent studies show that the use of GLP-1 RAs in obese males may enhance sperm metabolism, motility, and insulin secretion in vitro, along with positive effects on the human Sertoli cells. Recent clinical trials discussed in this review demonstrate weight loss associated with GLP-1 RAs is correlated with improvements in sperm count, concentration, and motility. However, the direct impact of GLP-1 RAs on male reproductive hormones remains unclear, necessitating further research to confirm their potential role in treating male infertility. Conclusions-This narrative review summarizes the existing literature discussing the potential impact of GLP-1 RA on the male reproductive system, emphasizing their potential therapeutic role in addressing idiopathic infertility in obese men. Despite numerous studies exploring the influence of GLP-1 and GLP-1 RAs on reproductive hormones, testicular function, and spermatogenesis, further clinical trials are crucial to validate initial evidence. Longer follow-up periods are essential to address uncertainties regarding the long-term repercussions and outcomes of GLP-1 RA use. While this holds true, the current literature suggests that GLP-1RAs show promise as a potential therapeutic approach for improving sperm parameters in obese men.

Modulatory effect of liraglutide on doxorubicin-induced testicular toxicity and behavioral abnormalities in rats: role of testicular-brain axis

Doxorubicin (DOX) is a powerful chemotherapeutic agent used in many types of malignancies. However, its use results in testicular damage. DOX-induced testicular damage results in low level of serum testosterone which may affect cognitive function. The current study investigated the protective effect of liraglutide (50, 100 μg/kg/day) in testicular toxicity and the consequent cognitive impairment induced by DOX. DOX treatment reduced sperm count (62%) and sperm motility (53%) and increased sperm abnormalities (786%), as compared to control group. DOX also reduced serum testosterone level (85%) and the gene expression of testicular 3β-HSD (68%) and 17β-HSD (82%). Moreover, it increased testicular oxidative stress (MDA and GSH) by 103% and 59%, respectively, apoptotic (caspase-3 and P53) by 996% and 480%, respectively. In addition, DOX resulted in increasing autophagic markers including PAKT, mTOR, and LC3 by 48%, 56%, and 640%, respectively. Additionally, rats' behavior in Y-maze (60%) and passive avoidance task (85%) was disrupted. The histopathological results of testis and brain supported the biochemical findings. Treatment with liraglutide (100 μg/kg/day) significantly abrogated DOX-induced testicular damage by restoring testicular architecture, increasing sperm count (136%) and sperm motility (106%), and decreasing sperm abnormalities (84%) as compared to DOX group. Furthermore, liraglutide increased serum testosterone (500%) and steroidogenesis enzymes 3β-HSD (105%) and 17β-HSD (181%) along with suppressing oxidative stress (MDA and GSH) by 23% and 85%, respectively; apoptotic (caspase-3 and P53) by 59% and55%, respectively; and autophagic markers including PAKT, mTOR, and LC3 by 48%, 97%, and 60%, respectively. Moreover, it enhanced the memory functions in passive avoidance and Y-maze tests (132%). In conclusion, liraglutide is a putative agent for protection against DOX-induced testicular toxicity and cognitive impairment through its antioxidant, antiapoptotic, and antiautophagic effects.

Positive effects of dietary supplementation with nutraceuticals on male subclinical hypogonadism: a pilot study

BACKGROUND

Lifestyle modifications (i.e., physical activity [PA] and lower dietary intake) often are not sufficient to improve testosterone (TE) levels and promote weight loss in men with metabolic hypogonadism. The aim of the study was to investigate the effects of a nutraceutical formulation containing myoinositol, alpha lipoic acid, folic acid and SelectSIEVE® as add-on treatment to lifestyle modifications in improving obesity-related subclinical hypogonadism.

METHODS

Body composition, insulin resistance, testicular and erectile function were investigated in 15 males (age=39.5±14.5 years; Body Mass Index [BMI]=30.2±3.8 kg/m2, with subclinical hypogonadism (TE levels <14 and normal luteinizing hormone [LH]). After a run-in three months unsupervised PA period (T1), the nutraceutical supplement was administered two-times per day for three additional months (T2).

RESULTS

BMI, the percentage fat mass, insulinemia and Homeostasis Model Assessment Index (P<0.01) along with glycemia (P<0.05) were significantly reduced at T2 compared to T1, respectively; fat free mass (FFM) was significantly higher at T2 compared to T1 (P<0.01). Also, TE, LH and 5-item international index of erectile function score were significantly increased at T2 compared to T1 (P<0.01), respectively.

CONCLUSIONS

The combination of unsupervised PA and nutraceutical supplement improves body composition, insulin sensitivity and TE production in overweight-obese men with metabolic hypogonadism. Further controlled studies in the long-term are warranted to elucidate potential changes in fertility.

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.

Liraglutide ameliorates diabetic-induced testicular dysfunction in male rats: role of GLP-1/Kiss1/GnRH and TGF-β/Smad signaling pathways

Introduction: Glucagon-like peptide -1 (GLP-1) is released by intestinal cells to stimulate glucose-dependent insulin release from the pancreas. GLP-1 has been linked to ameliorating obesity and/or diabetic complications as well as controlling reproductive function. Liraglutide is a GLP-1 receptor agonist (GLP-1RA) with 97% homology with GLP-1. The main objective of this study was to investigate the ameliorative role of liraglutide in diabetic-induced reproductive dysfunction in male rats. Methods: Rats were randomly allocated into 3 groups; a control group, a diabetic group, and a liraglutide-treated diabetic group. Results: In the diabetic group, a significant increase in BMI, FBG, HbA1c, HOMA-IR, TC, TAG, LDL, IL6, TNFα, and MDA, as well as decreased serum insulin, HDL, GSH, total testosterone, LH, and FSH, were shown compared to the control group. Furthermore, A significant downregulation in relative hypothalamic gene expression of GLP-1R, PPAR-α, PGC-1α, kiss, kiss1R, leptin, leptin R, GnRH GLP-1R, testicular PGC-1α, PPARα, kiss1, kiss1R, STAR, CYP17A1, HSD17B3, CYP19A, CYP11A1, and Smad7, as well as upregulation in hypothalamic GnIH and testicular TGF- β and Smad2 expression, were noticed compared to the control group. Liraglutide treatment significantly improved such functional and structural reproductive disturbance in diabetic rats. Conclusion: GLP-1RAs ameliorated the deleterious effects of diabetes on reproductive function by targeting GLP-1/leptin/kiss1/GnRH, steroidogenesis, and TGF- β/Smad pathways.

Summary of the clinical practice manual for late-onset hypogonadism

Testosterone plays an important role in maintaining both physical and mental function. Age-related testosterone depletion contributes to the development of angina, arteriosclerosis, obesity, metabolic syndrome, dementia, frailty, and a range of other conditions. A condition involving age-related testosterone depletion and the associated clinical symptoms is defined as late-onset hypogonadism (LOH). LOH is treated by testosterone replacement therapy. Indications for testosterone replacement therapy are determined by evaluating symptoms and signs.

Effects of treatment for diabetes mellitus on testosterone concentrations: A systematic review

BACKGROUND

Low testosterone levels are frequently present in men with obesity and insulin resistance. Currently available treatment options (testosterone replacement therapy or lifestyle changes) hold possible risks or are insufficient. Since low testosterone levels are closely related to obesity and type 2 diabetes, treatment modalities for these conditions could result into improvement of testosterone levels.

OBJECTIVES

To summarize the available evidence on the effects of traditional and recent treatment modalities for diabetes mellitus on testosterone levels and androgen-deficiency-related signs and symptoms.

MATERIALS AND METHODS

PubMed was searched from the year 2000 till present using MESH terms: "hypogonadism," "testosterone," "testosterone deficiency," "functional hypogonadism," and the different classes of medications. Studies with observational and experimental designs on humans that evaluated the effect of antidiabetic medications on gonadotropins and testosterone were eligible for inclusion.

RESULTS

Current available data show no or only limited improvement on testosterone levels with the classic antidiabetic drugs. Studies with GLP1-receptor analogues show beneficial effects on both body weight and testosterone levels in men with low testosterone levels and obesity with or without type 2 diabetes. However, data are limited to small and heterogeneous study groups and only few studies report data about impact on androgen-deficiency-related signs and symptoms.

DISCUSSION AND CONCLUSION

With the recent advances in the knowledge of the pathophysiological pathways in obesity, there is an enormous progress in the development of medications for obesity and type 2 diabetes. Newer incretin-based agents have a great potential for the treatment of functional hypogonadism due to obesity since they show promising weight reducing results. However, before the use of GLP1-receptor analogues can be suggested to treat functional hypogonadism, further studies are needed.

Sexual and Reproductive Outcomes in Obese Fertile Men with Functional Hypogonadism after Treatment with Liraglutide: Preliminary Results

Purpose: To prospectively investigate the effects of treatment with liraglutide, a glucagon-like peptide 1 (GLP1) analog, on reproductive and sexual function in men with metabolic hypogonadism who are of childbearing age. Materials and Methods: To accomplish this purpose, 110 men of childbearing age (18-35 years) with metabolic hypogonadism were enrolled and divided into three groups, according to their desire to have children. Group A was made up of men actively seeking fatherhood, Group B, of men who did not seek fatherhood, and Group C, of men who had already fathered a child. Group A patients were treated with gonadotropins (urofollitropin at 150 IU, three times a week, and human chorionic gonadotropin at 2000 IU, twice a week), Group B patients with liraglutide (3 mg daily), and Group C patients with transdermal testosterone (60 mg per day). All patients were treated for 4 months. Results: Patients treated with liraglutide (Group B) showed significant improvement in conventional sperm parameters, compared to baseline and Group A patients, and in the quality of erectile function compared to baseline and patients of Groups A and C. In addition, they had significantly higher levels of total testosterone and sex hormone-binding globulin serum levels after 4 months of treatment with liraglutide than those achieved by patients in the other two groups at the end of the respective treatments. Finally, Group B patients also showed significantly higher serum gonadotropin levels than the other groups. Conclusions: The results of this study showed, for the first time, the efficacy of liraglutide, a GLP1 analog, for the pharmacological treatment of male patients with metabolic hypogonadism. Liraglutide has also shown advantages over traditional treatments on both reproductive and sexual function and appears to offer greater benefits in terms of metabolic protection. These findings suggest that liraglutide is a useful drug for the treatment of obese males with metabolic hypogonadism.

Clinical Impact of Glucagon-Like Peptide-1 Receptor Analogs on the Complications of Obesity

BACKGROUND

Obesity is a chronic disease associated with increased morbidity and mortality due to its complications. The aims of obesity treatment are primarily to accomplish weight loss, and prevention or treatment of its complications. Lifestyle changes along with behavioral therapy constitute the first-line treatment of obesity followed by pharmacotherapy. Glucagon-like peptide receptor analogs (GLP-1 RAs) are among the approved pharmacotherapy options. Their central effect on suppressing appetite results in considerable weight loss. However, their effect on the complications of obesity has not been very well recognized. This review aims to analyze the effects of GLP-1 RAs on the complications of obesity, as diabetes mellitus, hypertension, nonalcoholic steatohepatitis (NASH), cardiovascular diseases, polycystic ovary syndrome, infertility, obstructive sleep apnea (OSA), osteoarthritis, cancer and central nervous system problems.

SUMMARY

Data from preclinical studies and clinical trials have been thoroughly evaluated. Effects regarding the complications as far as the scope of this review have covered can be summarized as blood glucose lowering, blood pressure lowering, resolution of NASH, improving major cardiovascular events, improving fertility and sex hormone levels, and improvement in OSA symptoms and in cognitive scores. Although the mechanisms are not fully elucidated, it is clear that the effects are not solely due to weight loss, but some pleiotropic effects like decreased inflammation, oxidative stress, and fibrosis also play a role in some of the complications.

KEY MESSAGES

Treating obesity is not only enabling weight loss but ameliorating complications related to obesity. Thus, any antiobesity medication has to have some favorable effects on the complications. As far as the GLP-RA's analogs are concerned, there seems to be an improvement in many of the complications regardless of the weight loss effect of these medications.

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.

Evidence for Involvement of GIP and GLP-1 Receptors and the Gut-Gonadal Axis in Regulating Female Reproductive Function in Mice

Substantial evidence suggests crosstalk between reproductive and gut-axis but mechanisms linking metabolism and reproduction are still unclear. The present study evaluated the possible role of glucose-dependent-insulinotropic-polypeptide (GIP) and glucagon-like-peptide-1 (GLP-1) in reproductive function by examining receptor distribution and the effects of global GIPR and GLP-1R deletion on estrous cycling and reproductive outcomes in mice. GIPR and GLP-1R gene expression were readily detected by PCR in female reproductive tissues including pituitary, ovaries and uterine horn. Protein expression was confirmed with histological visualisation of incretin receptors using GIPR-Cre and GLP1R-Cre mice in which the incretin receptor expressing cells were fluorescently tagged. Functional studies revealed that female GIPR^-/- and GLP-1R^-/- null mice exhibited significantly (p < 0.05 and p < 0.01) deranged estrous cycling compared to wild-type controls, indicative of reduced fertility. Furthermore, only 50% and 16% of female GIPR^-/- and GLP-1R^-/- mice, respectively produced litters with wild-type males across three breeding cycles. Consistent with a physiological role of incretin receptors in pregnancy outcome, litter size was significantly (p < 0.001-p < 0.05) decreased in GIPR^-/- and GLP-1R^-/- mice. Treatment with oral metformin (300 mg/kg body-weight), an agent used clinically for treatment of PCOS, for a further two breeding periods showed no amelioration of pregnancy outcome except that litter size in the GIPR^-/- group was approximately 2 times greater in the second breeding cycle. These data highlight the significance of incretin receptors in modulation of female reproductive function which may provide future targets for pharmacological intervention in reproductive disorders.

Gut hormones and reproduction (Hormones intestinalis et reproduction)

Reproduction and metabolism are intricately linked. Gut hormones play key roles in the regulation of body weight and glucose homeostasis, factors that influence the functioning of the hypothalamic-pituitary-gonadal axis and reproductive outcomes. Data from rodent models suggest gut hormones may have direct stimulatory effects on reproductive hormone release. However, the effects of gut hormones on reproductive function in humans is more complex, with possible involvement of direct (e.g. via gut hormone receptor agonism) as well as indirect (e.g. via weight reduction in people with obesity) mechanisms. The use of gut hormone receptor agonists has become an integral part of the management of metabolic diseases (including obesity and type 2 diabetes), with additional indications for their use on the horizon. Future work may identify specific roles for gut hormones receptor agonists in the treatment of reproductive co-morbidities that are increasingly being recognised in people with metabolic diseases.

The Interaction of Obesity and Reproductive Function in Adolescents

Obesity is increasing worldwide, including in pediatrics. Adequate nutrition is required for initiation of menses, and there is a clear secular trend toward earlier pubertal onset and menarche in females in countries around the globe. Similar findings of earlier pubertal start are suggested in males. However, as individuals and populations have crossed into over-nutritional states including overweight and obesity, the effect of excess weight on disrupting reproductive function has become apparent. Hypothalamic hypogonadism and polycystic ovary syndrome are two conditions where reproductive function appears to directly relate to excess weight. Clinical findings in individuals with certain polygenic and monogenic obesity syndromes, which also have reproductive disruptions, have helped elucidate neurologic pathways that are common to both. Clinical endocrinopathies such as hypothyroidism or panhypopituitarism also aide in the understanding of the role of the endocrine system in weight gain. Understanding the intersection of obesity and reproductive function may lead to future therapies which can treat both conditions.

ENDOCRINE OBESITY: Pituitary dysfunction in obesity

Obesity, the growing pandemic of the 21st century, is associated with multiple organ dysfunction, either by a direct increase in fatty organ content or by indirect modifications related to general metabolic changes driven by a specific increase in biologic products. The pituitary gland is not protected against such a situation. Different hypothalamic-pituitary axes experience functional modifications initially oriented to an adaptive situation that, with years of obesity, turn to maladaptive dynamics that contribute to perpetuating obesity and specific symptoms of their hormonal nature. This paper reviews the recent knowledge on obesity-related pituitary dysfunction and its pathogenic mechanisms and discusses potential therapeutic actions aimed at contributing to ameliorating the complex treatment of severe cases of obesity.

Erectile dysfunction and diabetes: A melting pot of circumstances and treatments

Diabetes mellitus (DM), a chronic metabolic disease characterised by elevated levels of blood glucose, is among the most common chronic diseases. The incidence and prevalence of DM have been increasing over the years. The complications of DM represent a serious health problem. The long-term complications include macroangiopathy, microangiopathy and neuropathy as well as sexual dysfunction (SD) in both men and women. Erectile dysfunction (ED) has been considered the most important SD in men with DM. The prevalence of ED is approximately 3.5-fold higher in men with DM than in those without DM. Common risk factors for the development of DM and its complications include sedentary lifestyle, overweight/obesity and increased caloric consumption. Although lifestyle changes may help improve sexual function, specific treatments are often needed. This study aims to review the definition and prevalence of ED in DM, the impact of DM complications and DM treatment on ED and, finally, the current and emerging therapies for ED in patients with DM.

The Effects of the New Therapeutic Treatments for Diabetes Mellitus on the Male Reproductive Axis

One of the complications of chronic hyperglycemia and insulin resistance due to type 2 diabetes mellitus (T2DM) on the hypothalamic-pituitary-gonadal axis in men, is the high prevalence of hypogonadotropic hypogonadism, which has been recently defined as functional hypogonadism, characterized by low testosterone associated with inappropriately normal gonadotropin levels. Although the pathophysiology of this hormonal imbalance may be related to several factors, including glycemic control, concomitant sleep apnea, insulin resistance, the main role is determined by the degree of central or visceral obesity and the consequent inflammatory state. Several drugs have been developed to treat T2DM such as glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase 4 inhibitors, and sodium-glucose co-transporter 2 inhibitors. All appear to be effective in ameliorating blood glucose control, by lowering inflammation and body weight, and most seem to reduce the risk of micro- and macrovascular damage as a consequence of uncontrolled diabetes. A few studies have evaluated the impact of these drugs on gonadal function in T2DM patients with hypogonadism, with promising results. This review summarizes the main current knowledge of the effects of these new antidiabetic drugs on the hypothalamus-pituitary-gonadal axis, showing their potential future application in addition to glucose control in dysmetabolic male patients.

Approach to Obesity in the Older Population

Until recently, weight loss in older obese people was feared because of ensuing muscle loss and frailty. Facing overall increasing longevity, high rates of obesity in older individuals (age ≥ 65 years) and a growing recognition of the health and functional cost of the number of obesity years, abetted by evidence that intentional weight loss in older obese people is safe, this approach is gradually, but not unanimously, being replaced by more active principles. Lifestyle interventions that include reduced but sufficient energy intake, age-adequate protein and micronutrient intake, coupled with aerobic and resistance exercise tailored to personal limitations, can induce weight loss with improvement in frailty indices. Sustained weight loss at this age can prevent or ameliorate diabetes. More active steps are controversial. The use of weight loss medications, particularly glucagon-like peptide-1 analogs (liraglutide as the first example), provides an additional treatment tier. Its safety and cardiovascular health benefits have been convincingly shown in older obese patients with type 2 diabetes mellitus. In our opinion, this option should not be denied to obese individuals with prediabetes or other obesity-related comorbidities based on age. Finally, many reports now provide evidence that bariatric surgery can be safely performed in older people as the last treatment tier. Risk-benefit issues should be considered with extreme care and disclosed to candidates. The selection process requires good presurgical functional status, individualized consideration of the sequels of obesity, and reliance on centers that are highly experienced in the surgical procedure as well as short-term and long-term subsequent comprehensive care and support.

Liraglutide treatment counteracts alterations in adipose tissue metabolism induced by orchiectomy in rats

AIMS

The reduction in androgens serum concentration is a physiological condition that accompanies age advancement but can also occur because of prostate cancer and gender affirming treatment or pathological conditions such as functional hypogonadism. However, androgen deficiency is related to a higher risk of developing metabolic disorders such as obesity and type 2 diabetes mellitus (T2DM). Considering that glucagon-like peptide 1 (GLP1) analogs are increasingly used in the treatment of T2DM, we investigated if liraglutide could also attenuate the metabolic changes caused by orchiectomy in rats.

MAIN METHODS

Wistar rats were orchiectomized (ORC), and subdivided in four groups: sham saline, sham liraglutide, ORC saline, and ORC liraglutide. After sixty days, metabolic parameters were evaluated in blood, muscle, liver, brown (BAT) and white adipose tissue (WAT) visceral depots. Glucose utilization, oxidation, and conversion to lipids by de novo lipogenesis, and basal and adrenaline-stimulated lipolysis were evaluated in BAT and WAT depots.

KEY FINDINGS

Orchiectomy increased triglyceridemia, BAT and rtWAT weight, and lipolysis and reduced glucose utilization. Liraglutide treatment reversed these effects.

SIGNIFICANCE

These results indicate that liraglutide improves triglyceridemia and glucose metabolism in WAT depots, which suggests that it may be a promising therapeutic strategy to handle disruptions in energy metabolism caused by androgen deficiency.

Is there a role for glucagon-like peptide-1 receptor agonists in the treatment of male infertility?

Glucagon‐like peptide‐1 receptor agonists (GLP1‐RAs) are novel anti‐hyperglycemic drugs efficacious on glucose control, weight loss, and cardiovascular prevention. These drugs may also be effective in modulating testicular function. In fact, they increase serum testosterone levels in diabetic and/or obese patients with functional hypogonadism on a dysmetabolic basis. Although part of this effect can be ascribed to weight loss, some evidence suggests that there is a direct effect at the testicular level. Indeed, human Leydig, Sertoli, and germ cells express GLP1 receptors. GLP1‐RAs improve sperm metabolism, motility, and insulin secretion in vitro. Likewise, GLP1‐RAs exert positive effects on the metabolism of human Sertoli cells in vitro. Finally, GLP1 is secreted by mouse Leydig cells and this suggests the presence of a paracrine mechanism by which these cells could support the metabolism of Sertoli cells. Therefore, the widespread use of GLP1‐RAs in clinical practice may reveal an important role in the management of male infertility in obese and/or diabetic patients given the negative impact of these diseases on testicular steroidogenesis and spermatogenesis. This should suggest the design of randomized controlled studies aimed at evaluating the effects of these drugs on testicular function.

Neutral effect of exenatide on serum testosterone in men with type 2 diabetes mellitus: A prospective cohort

BACKGROUND

Endogenous testosterone increases with weight loss from diet, exercise, and bariatric surgery. However, little is known about testosterone levels after weight loss from medication.

OBJECTIVES

Uncover the effects of Glucagon-Like Peptide-1 receptor agonist (GLP-1 RA) therapy on serum testosterone.

MATERIAL AND METHODS

Prospective cohort study of men starting GLP-1 RA therapy for type 2 diabetes mellitus.

RESULTS

51 men lost 2.27 kg (p = 0.00162) and their HbA1c values improved by 0.7% (p = 0.000503) after 6 months of GLP-1 RA therapy. There was no significant change in testosterone for the group as a whole. However, in subgroup analyses, there was a significant difference in total testosterone change between men starting with baseline total testosterone <320 ng/dL (238.5 ± 56.5 ng/dL to 272.2 ± 82.3 ng/dL) compared to higher values (438 ± 98.2 ng/dL to 412 ± 141.2 ng/dL) (p = 0.0172);free testosterone increased if the baseline total testosterone was <320 ng/dL (55.2 ± 12.8 pg/mL to 57.2 ± 17.6 pg/mL) and decreased if >320 ng/dL (74.7 ± 16.3 pg/mL to 64.2 ± 17.7 pg/mL) (p = 0.00807). Additionally, there were significant differences in testosterone change between men with HbA1c improvements ≥1% (351.6 ± 123.9 ng/dL to 394.4 ± 136.5 ng/dL) compared to men with HbA1c changes <1% (331.8 ± 128.6 ng/dL to 316.1 ± 126.2 ng/dL) (p = 0.0413).

CONCLUSION

GLP-1 RA therapy improves weight and HbA1c without adverse effects on testosterone. Those starting with lower testosterone values or attaining greater improvement in HbA1c may see additional benefits.

Kisspeptin-52 partially rescues the activity of the hypothalamus-pituitary-gonadal axis in underweight male rats dosed with an anti-obesity compound

Energy metabolism and reproduction are closely linked and reciprocally regulated. The detrimental effect of underweight on reproduction complicates the safety evaluation of anti-obesity drugs, making it challenging to distinguish pathological changes mediated through the intended drug-induced weight loss from direct drug effects on reproductive organs. Four-weeks dosing of normal weight Sprague Dawley rats with a glucagon-like peptide 1 (GLP-1)/glucagon receptor co-agonist induced a robust weight loss, accompanied by histological findings in prostate, seminal vesicles, mammary glands, uterus/cervix and vagina. Characterization of the hypothalamus-pituitary-gonadal (HPG) axis in male rats revealed reduced hypothalamic Kiss1 mRNA levels and decreased serum luteinizing hormone (LH) and testosterone concentrations following co-agonist dosing. These alterations resemble hypogonadotropic hypogonadism typically seen in adverse energy deprived conditions, like chronic food restriction. Concomitant daily administration of kisspeptin-52 from day 21 to the end of the four-week co-agonist dosing period evoked LH and testosterone responses without normalizing histological findings. This incomplete rescue by kisspeptin-52 may be due to the rather short kisspeptin-52 treatment period combined with a desensitization observed on testosterone responses. Concomitant leptin treatment from day 21 did not reverse co-agonist induced changes in HPG axis activity. Furthermore, a single co-agonist injection in male rats slightly elevated LH levels but left testosterone unperturbed, thereby excluding a direct acute inhibitory effect on the HPG axis. Our data suggest that the reproductive phenotype after repeated co-agonist administration was driven by the intended weight loss, however, we cannot exclude a direct organ related effect in chronically treated rats.

Acute Effects of Glucagon on Reproductive Hormone Secretion in Healthy Men

CONTEXT

Glucagon increases energy expenditure; consequently, glucagon receptor agonists are in development for the treatment of obesity. Obesity negatively affects the reproductive axis, and hypogonadism itself can exacerbate weight gain. Therefore, knowledge of the effects of glucagon receptor agonism on reproductive hormones is important for developing therapeutics for obesity; but reports in the literature about the effects of glucagon receptor agonism on the reproductive axis are conflicting.

OBJECTIVE

The objective of this work is to investigate the effect of glucagon administration on reproductive hormone secretion in healthy young men.

DESIGN

A single-blinded, randomized, placebo-controlled crossover study was conducted.

SETTING

The setting of this study was the Clinical Research Facility, Imperial College Healthcare NHS Trust.

PARTICIPANTS

Eighteen healthy eugonadal men (mean ± SEM: age 25.1 ± 1.0 years; body mass index 22.5 ± 0.4 kg/m2; testosterone 21.2 ± 1.2 nmol/L) participated in this study.

INTERVENTION

An 8-hour intravenous infusion of 2 pmol/kg/min glucagon or rate-matched vehicle infusion was administered.

MAIN OUTCOME MEASURES

Luteinizing hormone (LH) pulsatility; LH, follicle-stimulating hormone (FSH), and testosterone levels were measured.

RESULTS

Although glucagon administration induced metabolic effects (insulin area under the curve: vehicle 1065 ± 292 min.µU/mL vs glucagon 2098 ± 358 min.µU/mL, P < .001), it did not affect LH pulsatility (number of LH pulses/500 min: vehicle 4.7 ± 0.4, glucagon 4.2 ± 0.4, P = .22). Additionally, there were no significant differences in circulating LH, FSH, or testosterone levels during glucagon administration compared with vehicle administration.

CONCLUSIONS

Acute administration of a metabolically active dose of glucagon does not alter reproductive hormone secretion in healthy men. These data are important for the continued development of glucagon-based treatments for obesity.

The role of glucagon-like peptide-1 in reproduction: from physiology to therapeutic perspective

BACKGROUND

Glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1 RAs) have become firmly established in the treatment of type 2 diabetes and obesity, disorders frequently associated with diminished reproductive health. Understanding of the role of GLP-1 and GLP-1 RAs in reproduction is currently limited and largely unaddressed in clinical studies.

OBJECTIVE AND RATIONALE

The purpose of this narrative review is to provide a comprehensive overview of the role of GLP-1 in reproduction and to address a therapeutic perspective that can be derived from these findings.

SEARCH METHODS

We performed a series of PubMed database systemic searches, last updated on 1 February 2019, supplemented by the authors' knowledge and research experience in the field. A search algorithm was developed incorporating the terms glucagon-like peptide-1, GLP-1, glucagon-like peptide-1 receptor, GLP-1R, or incretins, and this was combined with terms related to reproductive health. The PICO (Population, Intervention, Comparison, Outcome) framework was used to identify interventional studies including GLP-1 RAs and dipeptidyl peptidase-4 (DPP-4) inhibitors, which prevent the degradation of endogenously released GLP-1. We identified 983 potentially relevant references. At the end of the screening process, we included 6 observational (3 preclinical and 3 human) studies, 24 interventional (9 preclinical and 15 human) studies, 4 case reports, and 1 systematic and 2 narrative reviews.

OUTCOMES

The anatomical distribution of GLP-1 receptor throughout the reproductive system and observed effects of GLP-1 in preclinical models and in a few clinical studies indicate that GLP-1 might be one of the important modulating signals connecting the reproductive and metabolic system. The outcomes show that there is mostly stimulating role of GLP-1 and its mimetics in mammalian reproduction that goes beyond mere weight reduction. In addition, GLP-1 seems to have anti-inflammatory and anti-fibrotic effects in the gonads and the endometrium affected by obesity, diabetes, and polycystic ovary syndrome (PCOS). It also seems that GLP-1 RAs and DPP-4 inhibitors can reverse polycystic ovary morphology in preclinical models and decrease serum concentrations of androgens and their bioavailability in women with PCOS. Preliminary data from interventional clinical studies suggest improved menstrual regularity as well as increased fertility rates in overweight and/or obese women with PCOS treated with GLP-1 RAs in the preconception period.

WIDER IMPLICATIONS

GLP-1 RAs and DPP-4 inhibitors show promise in the treatment of diabetes and obesity-related subfertility. Larger interventional studies are needed to establish the role of preconception intervention with GLP-1 based therapies, assessing fertility outcomes in obesity, PCOS, and diabetes-related fertility problems. The potential impact of the dose- and exposure time-response of different GLP-1 RAs need further exploration. Future research should also investigate sex-specific variability of GLP-1 on reproductive outcomes, in particular on the gonads where the observations in males are most conflicting.

Effects of Glucagon-like Peptide-1 on the Reproductive Axis in Healthy Men

CONTEXT

Glucagon-like peptide-1 (GLP-1) potently reduces food intake and augments glucose-stimulated insulin secretion. Recent animal data suggest that GLP-1 may also influence reproduction. As GLP-1 receptor agonists are currently widely used in clinical practice to treat obesity/type 2 diabetes, it is necessary to determine the effects of GLP-1 on the reproductive system in humans.

OBJECTIVE

To investigate the effects of GLP-1 administration on the reproductive axis in humans.

DESIGN

Single-blind, randomized, placebo-controlled crossover study.

SETTING

Clinical Research Facility, Imperial College Healthcare NHS Trust.

PARTICIPANTS

Eighteen healthy men (mean age 24.7 ± 0.1years, mean BMI 22.1 ± 0.4kg/m2).

INTERVENTION

Eight-hour intravenous infusion of 0.8 pmol/kg/min GLP-1 or rate-matched vehicle infusion.

MAIN OUTCOME MEASURES

Number of luteinizing hormone (LH) pulses, LH, follicle-stimulating hormone (FSH), and testosterone levels.

RESULTS

The number of LH pulses (number of LH pulses/500 min: vehicle 4.2 ± 0.4, GLP-1 4.5 ± 0.3, P = 0.46), LH area under the curve (AUC) (vehicle 1518 ± 88min.IU/L, GLP-1 1524 ± 101min.IU/L, P = 0.95), follicle-stimulating hormone AUC (vehicle 1210 ± 112 min IU/L, GLP-1 1216 ± 112 min IU/L, P = 0.86), and testosterone AUC (vehicle 10893 ± 615 min nmol/L, GLP-1 11088 ± 792 min nmol/L, P = 0.77) did not significantly differ during vehicle and GLP-1 administration. Glucagon-like peptide-1 significantly reduced food intake (vehicle 15.7 ± 1.3 kcal/kg, GLP-1 13.4 ± 1.3 kcal/kg, P = 0.01).

CONCLUSIONS

In contrast to the animal literature, our data demonstrate that acute GLP-1 administration does not affect reproductive hormone secretion in healthy men.

Male and female sexual dysfunction in diabetic subjects: Focus on new antihyperglycemic drugs

The association between diabetes mellitus (and its micro- and macro-vascular complications) and erectile dysfunction is widely known and the presence of hypogonadism may further complicate sexual dysfunction and quality of life, given the association between hypogonadism and reduced libido, ejaculatory disorders, and depressive symptoms. However, the recent introduction of novel antidiabetic agents with a wide range of mechanism of action may have a significant impact both on male and female sexuality directly (by inducing side effects as urinary tract infections) and indirectly (improving metabolic status and reducing diabetes complications behind sexual dysfunctions). To date only few papers are reporting the sexual effects of these treatments and, often, these are not comparable in their results. Conversely, female sexual dysfunctions are somehow under-investigated. Data on prevalence is heterogeneous and specific pathogenic mechanisms, as well as the burden of psychological factors, are still heatedly debated. The aim of this narrative review is to summarize current knowledge and stressing out the need to diagnose male and female sexual dysfunctions also in light of the impact of treatments with novel antidiabetic agents. This would highlight the still unmet needs for sexual care in a diabetes care setting and could represent an incentive for future discussions, as well as a required theoretical starting point for studies on this subject.

Late-onset hypogonadism and lifestyle-related metabolic disorders

BACKGROUND

Late-onset hypogonadism (LOH) is a condition defined by low levels of testosterone (T), occurring in advanced age. LOH is promoted by senescence, which, in turn, has negative effects on male fertility. Interestingly, the impact of metabolic disorders on the male reproductive system has been the topic of several studies, but the association with LOH is still debatable.

OBJECTIVES

Herein, we discuss the hypothesis that the prevalence of metabolic abnormalities potentiates the effects of LOH on the male reproductive system, affecting the reproductive potential of those individuals.

MATERIAL AND METHODS

We analyzed the bibliography available, until June 2019, about LOH in relation to metabolic and hormonal dysregulation, sperm quality profiles and assisted-reproduction treatment outcomes.

RESULTS

LOH affects the hypothalamic-pituitary testis (HPT) axis. Additionally, metabolic disorders can also induce T deficiency, which is reflected in decreased male fertility, highlighting a possible connection. Indeed, T replacement therapy (TRT) is widely used to restore T levels. Although this therapy is unable to reverse all deleterious effects promoted by LOH on male reproductive function, it can improve metabolic and reproductive health.

DISCUSSION AND CONCLUSIONS

Emerging new evidence suggests that metabolic disorders may aggravate LOH effects on the fertility potential of males in reproductive age, by enhancing T deficiency. These results clearly show that metabolic disorders, such as obesity and diabetes, have a greater impact on causing hypogonadotropic hypogonadism than tissue senescence. Further, TRT and off-label alternatives capable of restoring T levels appear as suitable to improve LOH, while also counteracting comorbidities related with metabolic diseases.

Male Obesity Associated Gonadal Dysfunction and the Role of Bariatric Surgery

Obesity is an ever growing pandemic and a prevalent problem among men of reproductive age that can both cause and exacerbate male-factor infertility by means of endocrine abnormalities, associated comorbidities, and direct effects on the precision and throughput of spermatogenesis. Robust epidemiologic, clinical, genetic, epigenetic, and preclinical data support these findings. Clinical studies on the impact of medically induced weight loss on serum testosterone concentrations and spermatogenesis is promising but may show differential and unsustainable results. In contrast, literature has demonstrated that weight loss after bariatric surgery is correlated with an increase in serum testosterone concentrations that is superior than that obtained with only lifestyle modifications, supporting a further metabolic benefit from surgery that may be specific to the male reproductive system. The data on sperm and semen parameters is controversial to date. Emerging evidence in the burgeoning field of genetics and epigenetics has demonstrated that paternal obesity can affect offspring metabolic and reproductive phenotypes by means of epigenetic reprogramming of spermatogonial stem cells. Understanding the impact of this reprogramming is critical to a comprehensive view of the impact of obesity on subsequent generations. Furthermore, conveying the potential impact of these lifestyle changes on future progeny can serve as a powerful tool for obese men to modify their behavior. Healthcare professionals treating male infertility and obesity need to adapt their practice to assimilate these new findings to better counsel men about the importance of paternal preconception health and the impact of novel non-medical therapeutic interventions. Herein, we summarize the pathophysiology of obesity on the male reproductive system and emerging evidence regarding the potential role of bariatric surgery as treatment of male obesity-associated gonadal dysfunction.

Treatment of Functional Hypogonadism Besides Pharmacological Substitution

A dichotomic distinction between “organic” and “functional” hypogonadism is emerging. The former is an irreversible condition due to congenital or “acquired” “organic” damage of the brain centers or of the testis. Conversely, the latter is a potentially reversible form, characterized by borderline low testosterone (T) levels mainly secondary to age-related comorbidities and metabolic derangements, including metabolic syndrome (MetS). Life-style modifications, - here reviewed and, when possible, meta-analyzed -, have documented that weight-loss and physical exercise are able to improve obesity-associated functional hypogonadism and its related sexual symptoms. A rabbit experimental model, of MetS originally obtained in our lab, showed that endurance training (PhyEx) completely reverted MetS-induced hypogonadotropic hypogonadism by reducing hypothalamus inflammation and testis fibrosis eventually allowing for a better corpora cavernosa relaxation and response to sildenafil. Physicians should strongly adapt all the reasonable strategies to remove/mitigate the known conditions underlying functional hypogonadism, including MetS and obesity. Physical limitations, including reduced muscle mass and increased fat mass, along with low self-confidence, also due to the sexual problems, might limit a subject's propensity to increase physical activity and dieting. A short term T treatment trial, by improving muscle mass and sexual function, might help hypogonadal obese patients to overcome the overfed, inactive state and to become physically and psychologically ready for changing their lifestyle.

Male Obesity-related Secondary Hypogonadism - Pathophysiology, Clinical Implications and Management

The single most significant risk factor for testosterone deficiency in men is obesity. The pathophysiological mechanisms involved in male obesity-related secondary hypogonadism are highly complex. Obesity-induced increase in levels of leptin, insulin, proinflammatory cytokines and oestrogen can cause a functional hypogonadotrophic hypogonadism with the defect present at the level of the hypothalamic gonadotrophin-releasing hormone (GnRH) neurons. The resulting hypogonadism by itself can worsen obesity, creating a self-perpetuating cycle. Obesity-induced hypogonadism is reversible with substantial weight loss. Lifestyle-measures form the cornerstone of management as they can potentially improve androgen deficiency symptoms irrespective of their effect on testosterone levels. In selected patients, bariatric surgery can reverse the obesity-induced hypogonadism. If these measures fail to relieve symptoms and to normalise testosterone levels, in appropriately selected men, testosterone replacement therapy could be started. Aromatase inhibitors and selective oestrogen receptor modulators are not recommended due to lack of consistent clinical trial-based evidence.

Metabolic Disorders and Male Hypogonadotropic Hypogonadism

Several studies highlight that testosterone deficiency is associated with, and predicts, an increased risk of developing metabolic disorders, and, on the other hand, is highly prevalent in obesity, metabolic syndrome and type-2 diabetes mellitus. Models of gonadotropin releasing hormone deficiency, and androgen deprivation therapy in patients with prostate cancer, suggest that hypogonadotropic hypogonadism might contribute to the onset or worsening of metabolic conditions, by increasing visceral adiposity and insulin resistance. Nevertheless, in functional hypogonadism, as well as in late onset hypogonadism, the relationship between hypogonadotropic hypogonadism and metabolic disorders is bidirectional, and a vicious circle between the two components has been documented. The mechanisms underlying the crosstalk between testosterone deficiency and metabolic disorders include increased visceral adipose tissue and insulin resistance, leading to development of metabolic disorders, which in turn contribute to a further reduction of testosterone levels. The decrease in testosterone levels might be determined by insulin resistance-mediated and, possibly, pro-inflammatory cytokine-mediated decrease of sex hormone binding globulin, resulting in a temporary increased free testosterone available for aromatization to estradiol in visceral adipose tissue, followed by a subsequent decrease in free testosterone levels, due to the excess of visceral adipose tissue and aromatization; by a direct inhibitory effect of increased leptin levels on Leydig cells; and by a reduced gonadotropin secretion induced by estradiol, inflammatory mediators, leptin resistance, and insulin resistance, with the ultimate determination of a substantial hypogonadotropic hypogonadism. The majority of studies focusing on the effects of testosterone replacement therapy on metabolic profile reported a beneficial effect of testosterone on body weight, waist circumference, body mass index, body composition, cholesterol levels, and glycemic control. Consistently, several interventional studies demonstrated that correction of metabolic disorders, in particular with compounds displaying a greater impact on body weight and insulin resistance, improved testosterone levels. The aim of the current review is to provide a comprehensive overview on the relationship between hypogonadotropic hypogonadism and metabolism, by clarifying the independent role of testosterone deficiency in the pathogenesis of metabolic disorders, and by describing the relative role of testosterone deficiency and metabolic impairment, in the context of the bidirectional relationship between hypogonadism and metabolic diseases documented in functional hypogonadotropic hypogonadism. These aspects will be assessed by describing metabolic profile in men with hypogonadotropic hypogonadism, and androgenic status in men with metabolic disorders; afterwards, the reciprocal effects of testosterone replacement therapy and corrective interventions on metabolic derangements will be reported.