Effects of testosterone replacement and its pharmacogenetics on physical performance and metabolism

Updates on androgen replacement therapy and lower urinary tract symptoms: a narrative review

Lower urinary tract symptoms (LUTS) are caused by higher tension at the bladder neck level (due to fibrosis or stiffness) or benign prostatic hyperplasia, which causes static obstruction of the bladder outlet. Both forms cause a group of symptoms such as hesitancy, intermittency, weak stream, nocturia, urine frequency, and urgency. Additionally, LUTS (obstructive or irritative symptoms) are common in elderly men with hypogonadism, identified as the reduced testes capability in producing sex steroids and sperm, and are categorized as testosterone deficiency. Even though the mode of action (MoA) of testosterone therapy (TTh) on hypogonadal men needs more researched and understanding, the effectiveness of TTh in the development of male genital organs has been reported in several studies. This review shows the latest updates of TTh in LUTS including potential adverse effects, advantages, and disadvantages.

Society for Endocrinology guidelines for testosterone replacement therapy in male hypogonadism

Male hypogonadism (MH) is a common endocrine disorder. However, uncertainties and variations in its diagnosis and management exist. There are several current guidelines on testosterone replacement therapy that have been driven predominantly by single disciplines. The Society for Endocrinology commissioned this new guideline to provide all care providers with a multidisciplinary approach to treating patients with MH. This guideline has been compiled using expertise from endocrine (medical and nursing), primary care, clinical biochemistry, urology and reproductive medicine practices. These guidelines also provide a patient perspective to help clinicians best manage MH.

Ameliorative effect of Allium atroviolaceum on sperm quality in cyclophosphamide-treated mice

Background

Cyclophosphamide (CP) is an anti-neoplastic alkylating agent that is extensively used in different chemotherapy regimens. Adverse effects on the reproductive system, especially spermatogenesis, are one of the most important side effects of this drug. It is medically essential to use complementary and alternative drugs. Herbal drugs have long been used as a complementary treatment. Our purpose was to study the effect of hydroalcoholic Allium atroviolaceum L. extract on spermatogenesis in CP-treated mice.

Results

CP affected a significant decrease in sperm count, motility, viability, and morphology. Sperm count was significantly higher in the all extract groups than in the group of control (p<0.001) and CP group (p<0.001, p<0.01). Sperm motility was significantly greater in the extract (100 and 200mg/kg) groups than in the group of control (p<0.05 and <0.001). Sperm immotility and rotational movement were significantly higher in the CP group than in the CP+extract groups (p<0.001). The sperm viability was significantly greater in the CP+extract (200mg/kg) group than in the CP group (p<0.001). The number of headless sperm, sperm with initial tail, with coiled tail, and sperm with curved body, was significantly lower in the CP+extract (200mg/kg) group than in the CP group (p<0.001).

Conclusion

A. atroviolaceum extract treatment significantly improved CP-induced reproductive toxicity.

Assessment of reproductive function in male albino rat fed dietary meal supplemented with Mucuna pruriens seed powder

The occurrence of conflicting reports on the improvement of male reproductive function among humans fed diet containing the seed of Mucuna pruriens (MP) have raised a major concern in Nigeria. We assessed the effect of MP seed powder on the reproductive function in 32 adult male albino rats randomized to 4 groups of 8 rats each for 8 weeks. Group 1 (control) was given standard rat chow while groups 2, 3 and 4 were fed diets containing MP seed powder at 0.75 g, 1.5 g and 2.25 g respectively. Serum level of follicle stimulating hormone, testosterone, luteinizing hormone, oxidative stress markers in the testis, epididymal sperm quality and cytoarchitectural structure of the testis were monitored using standard methods. Significant improvements (p < 0.05) in the serum levels of all the hormones, testicular antioxidant defence, epididymal sperm quality without testicular degenerative changes were observed in group 2 compared to other groups. Oxidative stress, severe degenerative architectural lesions in the testis as well as significant reductions (p < 0.05) in epididymal sperm count, percentage motility and significant (p < 0.05) increased in abnormal sperm cells were observed in group 4. MP seed enhances reproductive function in male rats only at a dose level of 0.75g. A dose value higher than 0.75 g may be toxic to the male reproductive system.

Sport, doping and male fertility

It is universally accepted that lifestyle interventions are the first step towards a good overall, reproductive and sexual health. Cessation of unhealthy habits, such as tobacco, alcohol and drug use, poor nutrition and sedentary behavior, is suggested in order to preserve/improve fertility in humans. However, the possible risks of physical exercise per se or sports on male fertility are less known. Being "fit" does not only improve the sense of well-being, but also has beneficial effects on general health: in fact physical exercise is by all means a low-cost, high-efficacy method for preventing or treating several conditions, ranging from purely physical (diabetes and obesity) to psychological (depression and anxiety), highly influencing male reproduction. If male sexual and reproductive health could be positively affected by a proper physical activity, inadequate bouts of strength - both excessive intensity and duration of exercise training - are more likely to have detrimental effects. In addition, the illicit use of prohibited drugs (i.e. doping) has reached pandemic proportions, and their actions, unfortunately very often underestimated by both amateur and professional athletes, are known to disrupt at different levels and throughout various mechanisms the male hypothalamic-pituitary-gonadal axis, resulting in hypogonadism and infertility.

The effect of flutamide on the physical working capacity and activity of some of the key enzymes for the energy supply in adult rats

The aim of the study was to assess the effects of androgen receptor antagonists on the physical working capacity and activity of some of the key muscle enzymes for the energy supply in rats. Young adult male Wistar rats were divided into two groups. One group received 15 mg kg⁻¹ of flutamide daily for 6 days a week and the other group served as control for 8 weeks. At the beginning and at the end of the experiment, all rats were subjected to submaximal running endurance (SRE), maximum time to exhaustion (MTE), and maximal sprinting speed (MSS) tests. At the end of the trial, maximum oxygen consumption (VO_2max) test was performed and the levels of testosterone, erythrocytes, hemoglobin as well as enzyme activity of succinate dehydrogenase (SDH), lactate dehydrogenase (LDH), and NAD.H2-cytochrome-c reductase (NAD.H2) of the gastrocnemius muscle were measured. Serum testosterone of the flutamide-treated rats was higher than that of the controls, which verifies the effectiveness of the dose chosen. MTE and SRE of the anti-androgen-treated group were lower compared with the initial values. Flutamide treatment decreased the activity of SDH and NAD.H2 compared with the controls. We found no effect of the anti-androgen treatment on MSS, VO_2max, running economy, LDH activity, and hematological variables. Our findings indicate that the maintenance of the submaximal and maximal running endurance as well as the activity of some of the key enzymes associated with muscle oxidative capacity is connected with androgen effects mediated by androgen receptors.

Effect of gasoline fumes on reproductive function in male albino rats

The increase in the frequency of exposure to gasoline fumes and the growing incidence of infertility among humans has been a major concern and subject of discussion over the years in Nigeria. We therefore present the reproductive effect of gasoline fumes on inhalation exposure in 40 male albino rats. The rats were randomized into five experimental treatments (T) with eight rats per treatment. T1 (control) was exposed to distilled water while T2, T3, T4, and T5 were exposed to gasoline fumes in exposure chambers for 1, 3, 5, and 9 h daily respectively for 12 weeks. Serum level of testosterone, follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin, oxidative stress markers in the testicular tissue, epididymal sperm health assessment, and testicular histopathology of the rats were used as a diagnostic marker of reproductive dysfunction. Significant (p < 0.05) alterations in the levels of all the reproductive hormones and oxidative stress markers assayed were observed in rats exposed to gasoline fume. Significant reductions (p < 0.05) in sperm count and percentage motility in the exposed rats were observed. Significant (p < 0.05) increased in abnormal sperm cells characterized by damaged head, bent tail, damaged tail, and without head were also observed in the exposed rats. Histopathologically, severe degenerative testicular architectural lesions characterized by alterations in all the generations of sperm cells and reduction of interstitial cells were seen in the exposed rats. Gasoline fume is thus said to interfere with spermatogenesis and impair fertility in male gonad.

Reproductive toxicity of Roundup herbicide exposure in male albino rat

The incidence of infertility in human is on the increase and the use of Roundup herbicide and presence of its residues in foodstuff is a major concern. This study therefore aim to assess the effect of Roundup on the reproductive capacity of 32 adult male albino rats randomized into 4 groups of 8 rats per group orally exposed to Roundup at 3.6mg/kg body weight(bw), 50.4mg/kgbw and 248.4mg/kgbw of glyphosate concentrations for 12 weeks while the control group was given distilled water. Serum level of reproductive hormone (testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH) and prolactin), oxidative stress indices in the testicular tissue, epididymal sperm morphology assessment and testicular histopathology of the rats were used as a diagnostic marker of reproductive dysfunction. Significant (p<0.05) alterations in the level of all the reproductive hormones and oxidative stress markers assayed were observed in rats exposed to Roundup. Significant reductions (p<0.05) in sperm count, percentage motility and significant (p<0.05) increased in abnormal sperm cells were observed in the exposed rats. Histopathologically, severe degenerative testicular architectural lesions were seen in the Roundup exposed rats. Roundup may interfere with spermatogenesis and impair fertility in male gonad.

Provocative stimulation of the hypothalamic-pituitary-testicular axis in men with spinal cord injury

STUDY DESIGN

Prospective study.

OBJECTIVE

To determine the integrity of the hypothalamic-pituitary-testicular axis in healthy men with spinal cord injury (SCI).

METHODS

Thirty healthy men with chronic SCI (37±10 years) and thirty-eight able-bodied (AB) controls (36±10 years) participated. Gonadotropin-releasing hormone (GnRH; 100 μg IV) was administered to determine gonadotropin release, and human chorionic gonadotropin (hCG; 4000 IU IM) was administered to determine testosterone (T) secretion. Responses to stimulation were categorized as 'responder' or 'non-responder' by clinical criteria. Single factor ANOVA with repeated measures was performed to identify group differences.

RESULTS

The proportion of responders to pituitary GnRH stimulation was similar in the SCI group (22 subjects (73%) for the follicular-stimulating hormone (FSH) and 23 subjects (76%) for the luteinizing hormone (LH) to that of the AB group. The SCI-responder group had an increased FSH response after stimulation compared with the AB-responder group (P<0.05). The SCI-responder group had a greater LH area under the curve to GnRH stimulation than the AB-responder group (P=0.06). The peak FSH response was at 60 min and the peak LH response at 30 min, regardless of group designation. All groups had similar increases in serum T concentration to hCG stimulation.

CONCLUSIONS

The pituitary response to stimulation in healthy men with SCI revealed an augmented FSH response; LH response only trended higher. The testicular response to provocative stimulation was similar in hypogonadal and eugondal subjects and in GnRH responders and non-responders. These findings suggest a lack of hypothalamic drive of pituitary gonadotropin release in healthy people with chronic SCI.

Ursodeoxycholic acid alleviates cholestasis-induced histophysiological alterations in the male reproductive system of bile duct-ligated rats

Ursodeoxycholic acid is the most widely used drug for treating cholestatic liver diseases. However, its effect on the male reproductive system alterations associated with cholestasis has never been studied. Thus, this study aimed to investigate the effect of ursodeoxycholic acid on cholestasis-induced alterations in the male reproductive system. Cholestasis was induced by bile duct ligation. Bile duct-ligated rats had higher cholestasis biomarkers and lower levels of testosterone, LH and FSH than did the Sham rats. They also had lower reproductive organs weights, and lower sperm motility, density and normal morphology than those of Sham rats. Histologically, these animals suffered from testicular tubular atrophy, interstitial edema, thickening of basement membranes, vacuolation, and depletion of germ cells. After ursodeoxycholic acid administration, cholestasis-induced structural and functional alterations were significantly ameliorated. In conclusion, ursodeoxycholic acid can ameliorate the reproductive complications of chronic cholestasis in male patients, which represents an additional benefit to this drug.

Gonadotropin secreting pituitary adenoma associated with erythrocytosis: case report and literature review

BACKGROUND

Most pituitary adenomas with FSH- or LH-positive immunohistochemistry are endocrinologically silent, and neurological symptoms due to their large volume are the first clinical signs; they are rarely reported to be secreting gonadotropins, this usually occurring in cases with clinical endocrine findings. Gonadotropinomas are often treated surgically because they are unresponsive to conventional medical therapies. Temozolomide was recently recommended for non-responder aggressive pituitary adenoma management.

CASE REPORT

A 43-year-old male with a history of 5 years of erythrocytosis presented with severe headache, orthostatic dizziness, and difficulty walking. MRI documented a giant pituitary adenoma and high uptake of 111In-pentetreotide indicated somatostatin receptor (SSR) expression. Biochemical tests revealed a secreting gonadotropinoma. Therapy with somatostatin analogs and dopamine agonists improved the patient's headache, achieved partial hormone control, slightly reduced the size of the adenoma, and controlled erythrocytosis. Six months after the diagnosis, hormone escape occurred despite therapy, thus neurosurgery was performed. After the procedure the patient died of untreatable intracranial hypertension. The surgical specimen revealed SSR 2 and 3 expression, and temozolomide did not induce apoptosis in primary cell culture.

REVIEW OF LITERATURE

Among gonadotropinomas, female gender (77%), macroadenoma (84%), young age at diagnosis (28 ± 12 years), delay from first symptoms to diagnosis (up to 15 years), and ovarian cysts/menstrual disorders in females or macro-orchidism in males were the foremost clinical and neuroimaging features.

CONCLUSIONS

Male gonadotropin-secreting pituitary adenomas may have a variable clinical expression secondary to testosterone excess. Somatostatin analogs, dopamine agonists or temozolomide may have a role that needs to be assessed case by case.

Serum testosterone levels and excessive erythrocytosis during the process of adaptation to high altitudes

Populations living at high altitudes (HAs), particularly in the Peruvian Andes, are characterized by a mixture of subjects with erythrocytosis (16 g dl(-1)<haemoglobin (Hb)≤21 g dl(-1)) and others with excessive erythrocytosis (EE) (Hb>21 g dl(-1)). Elevated haemoglobin values (EE) are associated with chronic mountain sickness, a condition reflecting the lack of adaptation to HA. According to current data, native men from regions of HA are not adequately adapted to live at such altitudes if they have elevated serum testosterone levels. This seems to be due to an increased conversion of dehydroepiandrosterone sulphate (DHEAS) to testosterone. Men with erythrocytosis at HAs show higher serum androstenedione levels and a lower testosterone/androstenedione ratio than men with EE, suggesting reduced 17beta-hydroxysteroid dehydrogenase (17beta-HSD) activity. Lower 17beta-HSD activity via Δ4-steroid production in men with erythrocytosis at HA may protect against elevated serum testosterone levels, thus preventing EE. The higher conversion of DHEAS to testosterone in subjects with EE indicates increased 17beta-HSD activity via the Δ5-pathway. Currently, there are various situations in which people live (human biodiversity) with low or high haemoglobin levels at HA. Antiquity could be an important adaptation component for life at HA, and testosterone seems to participate in this process.

Andrological aspects of physical exercise and sport medicine

Appropriate physical activity is one of the bases of healthy lifestyle. In fact, physical exercise and playing sport may be associated with both improvements and injury to both general and reproductive health. A biologically normal testosterone secretion appears fundamental in males to guarantee both a physiological exercise adaptation and safe sport participation. The reproductive system is highly sensitive to the effects of exercise-related stress and the reproductive hormones may both increase and decrease after different acute or chronic exercises. Exercise and sport participation may positively or negatively influence andrological health status depending on the type, intensity and duration of performed physical activity and on individual health status. In addition, prohibited substances administration (e.g. androgenic-anabolic steroids, and so forth) in competitive and non-competitive athletes represents the main cause of iatrogenic andrological diseases. Preventing and treating andrological problems in active healthy and unhealthy individuals is as important as promoting a correct lifestyle. Physicians need to be educated on the relationships between the male reproductive system and sport participation and on the great role of the pre-participation physical examination in the prevention of andrological diseases.

Relationship of obesity, androgen receptor genotypes and biochemical failure after radical prostatectomy

BACKGROUND

Obesity and androgen metabolism have been implicated in the progression of prostate cancer. Obesity has been associated with increased risk for advanced disease and biochemical failure after treatment. This association may be the result of changes in androgen metabolism that occur with obesity and are mediated by the androgen receptor (AR).

METHODS

To evaluate the effects of obesity and AR polymorphisms on biochemical failure, we conducted a study of 536 Caucasian prostate cancer cases. We determined the relationship between time to biochemical failure and obesity stratified by short and long AR-CAG and AR-GGN repeat sequence. The AR repeat groups were dichotomized at the median number of repeats for each polymorphism.

RESULTS

An association was found for obesity in the short CAG group (HR = 3.45, 95% CI = 1.00-11.96). Among obese patients diagnosed with localized disease (T1/T2), the risk of biochemical failure was significantly higher (HR = 7.05, 95% CI = 1.55-32.06). No difference was observed for high stage (T3/T4) obese patients. Additionally, no differences in biochemical failure were observed in obese and non-obese men grouped by number of AR-GGN repeats.

CONCLUSIONS

Obesity is significantly associated with increased risk of biochemical failure in men with the high-risk short CAG sequence on the AR gene. This effect is not observed in men with long CAG repeats. Therefore, it appears that the relationship between biochemical failure and obesity may be modified by the AR-CAG repeat pattern. The short AR-CAG genotype may be more responsive to an altered hormonal milieu created by obesity.

Correlation between Iron Status Parameters and Hormone Levels in Women with Polycystic Ovary Syndrome

Much research has shown that iron store parameters are increased in women with polycystic ovary syndrome (PCOS), but an exact explanation for this phenomenon remains unavailable. The objective of this study was to investigate the correlation between iron status parameters and hormonal disturbances in women with PCOS that accounts for their increased iron store levels. Iron status parameters and hormones were measured using colorimetric and enzyme-linked immunosorbent assays, respectively. The results demonstrated a mild iron overload in the patients with PCOS. Good positive correlations between iron status parameters and serum testosterone, prolactin, and insulin were detected in the patient group, whereas iron status parameters and BMI were not significantly correlated. The data also suggest that the increase in serum ferritin and body iron store levels in patients with PCOS are associated with hyperandrogenemia, hyperprolactinemia, and hyperinsulinemia. The findings of this study expand current knowledge on the factors affecting iron stores and suggest a different mechanism of interaction between iron stores and the endocrine system through the harmful deposition of iron in endocrine glands and through hormonal effects on iron absorption and metabolism.

Erectile dysfunction and its association with metabolic syndrome and endothelial function among patients with type 2 diabetes mellitus

CONTEXT

Evidence suggests that numerous comorbid conditions contribute to erectile dysfunction (ED) among patients with type 2 diabetes mellitus (T2DM).

OBJECTIVE

To review the relationship and mechanism between diabetes, metabolic syndrome, cardiovascular disease (CVD), and ED.

METHODS

A manual review of authoritative literature from peer-reviewed publications from January 2001 through July 2010 was performed. These publications were further mined to consider the impact of metabolic syndrome as a comorbid condition. Publications from key references were also consulted.

RESULTS

The associations between obesity, dyslipidemia, metabolic syndrome, T2DM, CVD, and depression with sexual dysfunction suggest that sexual dysfunction, particularly ED, is a precursor to CVD. Because these conditions share important risk factors with CVD, identifying them and their relationships with the pathogenesis of ED is likely to be critical to the manner in which primary care physicians screen for and manage this condition.

CONCLUSIONS

Primary care physicians ought to establish trusting relationships with their patients, providing opportunities for them to probe such sensitive issues as sexual activities, as a means of addressing the possibility of ED. When making the new diagnosis of sexual dysfunction in the absence of metabolic disease or CVD, physicians ought to consider the risk for T2DM and CVD. Associations between metabolic disease, heart disease, and sexual dysfunction further suggest that all patients who are obese and have dyslipidemia, T2DM, and/or depression should be further screened for ED.

High serum zinc and serum testosterone levels were associated with excessive erythrocytosis in men at high altitudes

Chronic mountain sickness (CMS), a lack of adaptation to altitude characterized by excessive erythrocytosis (EE), is a health problem associated with life at high altitude. The erythropoietic process is regulated by both erythropoietin and testosterone. Zinc (Zn) is known to be related with testosterone and hemoglobin levels; meanwhile, nitric oxide was also associated with adaptation to high altitude. The aim of this study was to determine the relationship of hemoglobin and CMS score with serum levels of zinc, total testosterone (TT), calculated free testosterone (cFT), bioavailable testosterone (BAT), hemoglobin, and nitric oxide in men at high altitude with or without EE. Men residing in Lima (150 m) and Cerro de Pasco (4,340 m), Peru, were divided into three groups: (1) low altitude, (2) high altitude without EE (hemoglobin < 21 g/dl), and (3) high altitude with EE (hemoglobin ≥ 21 g/dl). Adjusted multivariable regression models showed that serum testosterone (total or free) and Zn levels were independently correlated with increased hemoglobin levels. Similarly, hemoglobin was positively related with signs/symptoms of CMS; however, both increased the serum Zn and the nitric oxide levels correlated with reduced risk for signs/symptoms of CMS. In conclusion, higher serum testosterone levels and Zn levels were associated with EE, and low scores of signs/symptoms of CMS were associated with higher Zn and nitric oxide levels.

Testosterone or 17{beta}-estradiol exposure reveals sex-specific effects on glucose and lipid metabolism in human myotubes

Changes in sex hormone levels with aging or illness may lead to metabolic disorders. Moreover, the ratio changes in men versus women may have distinct pathological responses. Since little is known about sex hormone action on muscle metabolism, we examined the role of testosterone or 17β-estradiol (E(2)) in metabolism and investigated whether either hormone may mediate a sex-specific effect. Myotubes from postmenopausal women and age-matched male donors were treated with 10 nM testosterone or E(2) for 4 days, and assays were performed to measure metabolic readouts, signal transduction, and mRNA expression. Testosterone and E(2) treatment enhanced insulin-stimulated glucose incorporation into glycogen and AKT phosphorylation in myotubes from female donors, highlighting a sex-specific role of sex hormone in glucose metabolism. Testosterone treatment increased palmitate oxidation in myotubes from both female and male donors, while E(2) enhanced palmitate oxidation in myotubes from male donors only. Testosterone-mediated increase in palmitate oxidation was attenuated at the presence of androgen receptor antagonist, which may indicate a role of nuclear steroid receptor in muscle lipid oxidation. Testosterone treatment increased mRNA expression of the insulin receptor substrate 2 in myotubes from male and female donors, whereas it increased mRNA expression of glycogen synthase 1 only in myotubes from male donors. E(2) treatment increased pyruvate dehydrogenase kinase 4 mRNA expression in myotubes from female donors. Thus, our data suggest that testosterone or E(2) modulates muscle glucose and lipid metabolism and may play a role in metabolism in a sex-dependent manner.

Testosterone and coronary artery disease

Cardiovascular disease remains the leading cause of death in most of the developed world despite advances in both prevention and treatment. At the same time, the incidence rates of cardiovascular disease differ greatly between the genders, with men more likely than women to manifest ischemic heart disease. This observation has prompted new research initiatives to explain the discrepancy in heart disease prevalence and incidence between the sexes. Whether androgens affect cardiovascular disease adversely remains a contentious issue, with some data pointing to a deleterious effect of androgens on lipid profiles, and other studies revealing androgens' possible benefits on cardiovascular function. This review will examine the relationship between the endogenous production of androgen as well as the exogenous replacement of testosterone in men and the possible links to cardiovascular disease. The role of testosterone in male cardiovascular health is not completely understood, and additional studies are needed to explain its effect on atherosclerosis and its complications.

Chronic exposure to anabolic steroids induces the muscle expression of oxytocin and a more than fiftyfold increase in circulating oxytocin in cattle

Molecular mechanisms in skeletal muscle associated with anabolic steroid treatment of cattle are unclear and we aimed to characterize transcriptional changes. Cattle were chronically exposed (68 ± 20 days) to a steroid hormone implant containing 200 mg trenbolone acetate and 20 mg estradiol (Revalor-H). Biopsy samples from 48 cattle (half treated) from longissimus dorsi (LD) muscle under local anesthesia were collected. Gene expression levels were profiled by microarray, covering 16,944 unique bovine genes: 121 genes were differentially expressed (DE) due to the implant (99.99% posterior probability of not being false positives). Among DE genes, a decrease in expression of a number of fat metabolism-associated genes, likely reflecting the lipid storage activity of intramuscular adipocytes, was observed. The expression of IGF1 and genes related to the extracellular matrix, slow twitch fibers, and cell cycle (including SOX8, a satellite cell marker) was increased in the treated muscle. Unexpectedly, a very large 21- (microarray) to 97 (real time quantitative PCR)-fold higher expression of the mRNA encoding the neuropeptide hormone oxytocin was observed in treated muscle. We also observed an ∼50-fold higher level of circulating oxytocin in the plasma of treated animals at the time of biopsy. Using a coexpression network strategy OXTR was identified as more likely than IGF1R to be a major mediator of the muscle response to Revalor-H. A re-investigation of in vivo cattle LD muscle samples during early to mid-fetal development identified a >128-fold increased expression of OXT, coincident with myofiber differentiation and fusion. We propose that oxytocin may be involved in mediating the anabolic effects of Revalor-H treatment.

Genetic variation in androgen disposition: implications in clinical medicine including testosterone abuse

BACKGROUND

Testosterone replacement therapy in hypogonadal men has been used for > 60 years. The use of testosterone substitution is continuously growing and is given to aging men to improve the quality of life. Because testosterone use is associated with muscle strength enhancing effects, it has become a popular drug to abuse. Doping with anabolic steroids, such as testosterone, is a severe challenge to the vision, moral and ethics in sports and has also become a significant and increasing problem in society.

OBJECTIVE

The primary aim of this review is to summarize and discuss the contribution of genetic components to inter-individual variation in androgen disposition.

CONCLUSION

Genetic variation has a large impact on androgen disposition. This variation is of the utmost importance for the interpretation of doping test results and may modulate the effects of testosterone replacement therapy and testosterone doping.

Timetable of effects of testosterone administration to hypogonadal men on variables of sex and mood

INTRODUCTION

The effects of testosterone have been extensively characterized, but little attention has been given to the timetable of occurrence of the various effects of testosterone.

METHODS

The timetables of effects on sexual and psychological variables in 40 hypogonadal men receiving treatment with either parenteral testosterone enanthate (TE) or undecanoate (TU).

RESULTS

Sexual thoughts/fantasies and sexual interest/desire/spontaneous morning erections emerged quickly and plateaued after 3 weeks. Total erections rose to a maximum over 9 weeks and then plateaued. Ejaculations per week/satisfaction with sex life rose over the first 3 weeks, increasing steadily to a plateau at 12 weeks. Depression scores decreased to reach a plateau after 6 weeks. Aggressiveness did not change. Scores of concentration improved and reached a plateau after 3 weeks in the group treated with TE and after 9 weeks in the group treated with TU. Good mood improved after 6-9 weeks. Positive effects on self-confidence appeared between 3-6 weeks and on fatigue after 9-12 weeks.

CONCLUSION

Insight into the emergence of effects may be useful information for the patient and for the attending physician in monitoring clinical effects of testosterone treatment of hypogonadal men.

High serum testosterone levels are associated with excessive erythrocytosis of chronic mountain sickness in men

Chronic mountain sickness (CMS) is characterized by excessive erythrocytosis (EE) secondary to hypoventilation. Erythropoietin (Epo) and testosterone regulate erythrocyte production. Low thyroid hormone levels are also associated to hypoventilation. Hence, these hormones can play a role in etiopathogeny of EE. The purpose of this study was to elucidate the effect of sexual and thyroid hormones and Epo in residents from Lima (150 m) and Cerro de Pasco (4,340 m), Peru, and the response to human chorionic gonadotrophin stimulation (hCG). Three groups, one at low altitude and two at high altitude [1 with hemoglobin values >16-21 g/dl and the second with Hb >or=21 g/dl (EE)], were studied. hCG was administered intramuscularly in a single dose (1,000 IU), and blood samples were obtained at 0, 6, 12, 24, 48, and 72 h after injection. High-altitude natives present similar levels of gonadotropins and thyroid hormones but lower dehydroepiandrosterone sulphate (DHEAS) levels (P < 0.01) and greater Epo (P < 0.01), 17alpha-hydroxyprogesterone (P < 0.01), and testosterone levels (P < 0.01) than those at 150 m. Serum testosterone levels (524.13 +/- 55.91 microg/dl vs. 328.14 +/- 53.23 ng/dl, means +/- SE; P < 0.05) and testosterone/DHEAS ratios are higher (7.98 +/- 1.1 vs. 3.65 +/- 1.1; P < 0.01) and DHEAS levels lower in the EE group (83.85 +/- 14.60 microg/dl vs. 148.95 +/- 19.11 ug/dl; P < 0.05), whereas Epo was not further affected. Testosterone levels were highest and DHEAS levels lowest in the EE group at all times after hCG stimulation. In conclusion, high androgen activity could be involved in the etiopathogeny of CMS. This evidence provides an opportunity to develop new therapeutic strategies.