Age trends in the level of serum testosterone and other hormones in middle-aged men: longitudinal results from the Massachusetts male aging study

Estrogen-regulated development and differentiation of the prostate

Both androgens and estrogens play a significant role in the prostate and are critical for normal prostate growth and development, as well as the maintenance of adult prostatic homeostasis throughout life. It is the balance of these two hormones, rather than each individually, that is important for prostatic development and differentiation. Estrogen action is mediated by the estrogen receptors, ERalpha and ERbeta. ERalpha is expressed throughout the prostatic tissue during fetal and early neonatal life, and if activated inappropriately, produces late-life disease, including inflammation and emergence of pre-malignant pathologies. In contrast, ERbeta expression is initiated after ERalpha, is localized primarily to the epithelium, and appears to be important during later periods of development such as puberty and adulthood, acting to regulate cellular proliferation and differentiation in the adult tissue. Therefore, there is also a spatial and temporal balance between ERalpha and ERbeta that is critical for development. Together with the shifting balance between androgens and estrogens themselves, the subtle, yet critical, balance between the activity of ERalpha and ERbeta is what ultimately determines the response of the prostate to estrogen, and is crucial for prostate health.

Testosterone for the aging male; current evidence and recommended practice

An international consensus document was recently published and provides guidance on the diagnosis, treatment and monitoring of late-onset hypogonadism (LOH) in men. The diagnosis of LOH requires biochemical and clinical components. Controversy in defining the clinical syndrome continues due to the high prevalence of hypogonadal symptoms in the aging male population and the non-specific nature of these symptoms. Further controversy surrounds setting a lower limit of normal testosterone, the limitations of the commonly available total testosterone result in assessing some patients and the unavailability of reliable measures of bioavailable or free testosterone for general clinical use. As with any clinical intervention testosterone treatment should be judged on a balance of risk versus benefit. The traditional benefits of testosterone on sexual function, mood, strength and quality of life remain the primary goals of treatment but possible beneficial effects on other parameters such as bone density, obesity, insulin resistance and angina are emerging and will be reviewed. Potential concerns regarding the effects of testosterone on prostate disease, aggression and polycythaemia will also be addressed. The options available for treatment have increased in recent years with the availability of a number of testosterone preparations which can reliably produce physiological serum concentrations.

Association between lipid profile and circulating concentrations of estrogens in young men

OBJECTIVES

Men show higher rates of cardiovascular morbidity and mortality than pre-menopausal women and this sexual dimorphism may be related to sex-specific effects of sex steroids on cardiovascular risk factors. Unlike androgens, estrogens were not extensively investigated in relation to cardiovascular phenotypes in men.

METHODS

We examined associations of estradiol and estrone and their precursors (total testosterone and androstenedione) with traditional cardiovascular risk factors (lipids, blood pressure, body mass) in 933 young (median age: 19 years), apparently healthy Polish men.

RESULTS

Total estradiol was associated with total cholesterol (p=0.006) and high-density lipoprotein cholesterol (HDL-C) (p<0.001) and estrone showed the strongest associations with both total cholesterol (p<0.001) and low-density lipoprotein cholesterol (LDL-C) (p<0.001) in the unadjusted ANOVA analysis. In the multivariable adjusted models in which other independent variables were held as constant one standard deviation increase in estradiol level was associated with 6%-standard deviation increase in total cholesterol (standardized beta=0.06, p=0.038) and 6%-standard deviation decrease in HDL-cholesterol (standardized beta=-0.06, p=0.036). An increase in estrone levels by one standard deviation was associated with respective 12%- and 13%-standard deviation increases in total cholesterol (standardized beta=0.12, p<0.001) and LDL-cholesterol levels (standardized beta=0.12, p<0.001) after controlling for other predictors of lipids. Estrone correlated linearly with androstenedione (r=0.28, p<0.001) but there was no correlation between estradiol and testosterone. Estrogens retained their independent associations with lipids after adjustment for their biochemical precursors in the multivariable analysis.

CONCLUSIONS

Increased levels of estrogens are associated with unfavourable lipid profile in men and this association is present early in life, before apparent manifestations of cardiovascular disease.

Testosterone and depression in men

PURPOSE OF REVIEW

The purpose of the review is to update the current literature regarding the role, if any, that testosterone plays in depressive illness. We have considered the influences on depression of endogenous testosterone, that is, hypogonadism and depression; and exogenous testosterone, that is, as a potential antidepressant.

RECENT FINDINGS

Studies do not support a consistent relationship between testosterone level and mood. There may be vulnerable subpopulations in whom hypogonadism contributes to depression; and chronic depressive illness may lead to hypogonadism in some men. Results from multiple randomized, controlled clinical trials are conflicting. Most do not support testosterone as a broadly effective antidepressant, but it may be effective in carefully selected populations, such as hypogonadal men, antidepressant-resistant men, men with early onset depression, and/or HIV-infected men.

SUMMARY

There is little support for a pervasive influence of testosterone on mood.

The natural history of symptomatic androgen deficiency in men: onset, progression, and spontaneous remission

OBJECTIVES

To describe the onset, progression, and remission of symptomatic androgen deficiency (SAD) using longitudinal data from the Massachusetts Male Aging Study (MMAS).

DESIGN

A prospective, population-based study of men living in Boston, Massachusetts. Data were collected in three waves: T1 (1987/89), T2 (1995/97), T3 (2002/04). Onset, progression, and remission were defined in terms of transitions in SAD status from one wave to the next.

SETTING

In-person, in-home interviews.

PARTICIPANTS

Seven hundred sixty-six community-dwelling men aged 40 to 70 at baseline (T1) contributed data from T1 to T2 and 391 from T2 to T3.

MEASUREMENTS

SAD was defined in terms of serum total and free testosterone (T) levels and symptoms associated with low circulating androgens. Total T and sex hormone-binding globulin (SHBG) were measured using radioimmunoassay. Free T was calculated from total T and SHBG measurements.

RESULTS

At T2 or T3, the likelihood of SAD was markedly greater for subjects who had exhibited SAD at the previous wave (odds ratio=3.8, 95% confidence interval=1.9-7.4), overall 55% of subjects who exhibited SAD experienced remission by the next study wave. The probability of SAD was greater with older age and greater body mass index. Multivariate models demonstrated that the likelihood of remission was at least 50% for most subpopulations.

CONCLUSION

Over approximately 15 years of follow-up, SAD did not represent a stable health state. The likelihood of SAD would remit exceeded the likelihood that it would not, particularly among younger and leaner men.

Androgen cell signaling pathways involved in neuroprotective actions

As a normal consequence of aging in men, testosterone levels significantly decline in both serum and brain. Age-related testosterone depletion results in increased risk of dysfunction and disease in androgen-responsive tissues, including brain. Recent evidence indicates that one deleterious effect of age-related testosterone loss in men is increased risk for Alzheimer's disease (AD). We discuss recent findings from our laboratory and others that identify androgen actions implicated in protecting the brain against neurodegenerative diseases and begin to define androgen cell signaling pathways that underlie these protective effects. Specifically, we focus on the roles of androgens as (1) endogenous negative regulators of beta-amyloid accumulation, a key event in AD pathogenesis, and (2) neuroprotective factors that utilize rapid non-genomic signaling to inhibit neuronal apoptosis. Continued elucidation of cell signaling pathways that contribute to protective actions of androgens should facilitate the development of targeted therapeutic strategies to combat AD and other age-related neurodegenerative diseases.

Androgen increases AT1a receptor expression in abdominal aortas to promote angiotensin II-induced AAAs in apolipoprotein E-deficient mice

OBJECTIVE

Castration of male apolipoprotein E-deficient (apoE-/-) mice reduces angiotensin II (Ang II)-induced abdominal aorta aneurysms (AAAs) to that of female mice. The purpose of this study was to determine whether this reduction is attributable to androgen-mediated regulation of aortic Ang II type 1A receptors (AT1aR).

METHODS AND RESULTS

AT1aR mRNA abundance in the AAA-prone region of abdominal aortas was 8-fold greater compared to thoracic aortas of male but not female mice. AT1aR mRNA abundance decreased after castration in abdominal but not thoracic aortas of male mice. Dihydrotestosterone (DHT, 0.16 mg/d) administration to castrated male mice restored AT1aR mRNA abundance in abdominal aortas but had no effect in thoracic aortas. DHT also increased AT1aR mRNA abundance in abdominal aortas from female mice. Castrated male or female apoE-/- mice were administered DHT during infusion of saline or Ang II (1000 ng/kg/min for 28 days). DHT administration did not alter serum cholesterol concentrations, lipoprotein distributions, or atherosclerotic lesion areas in either male or female mice. However, administration of DHT increased AAA incidence in male (27% placebo versus 75% DHT) and female mice (28% placebo versus 64% DHT).

CONCLUSIONS

Androgen promotes AT1aR mRNA abundance in abdominal aortas associated with increased Ang II-induced AAAs.

Effect of exercise on serum sex hormones in men: a 12-month randomized clinical trial

PURPOSE

The effect of exercise on androgens in middle-aged to older men is poorly understood, and it could have implications for several aspects of health. This analysis was conducted to examine the effects of long-term aerobic exercise on serum sex hormones in middle-aged to older men.

METHODS

One hundred two sedentary men, ages 40-75 yr, were randomly assigned to a 12-month exercise intervention or a control group (no change in activity). The combined facility- and home-based exercise program consisted of moderate/vigorous-intensity aerobic activity for 60 min.d(-1), 6 d.wk(-1). Serum concentrations of testosterone, free testosterone, dihydrotestosterone (DHT), 3alpha-androstanediol glucuronide (3alpha-Diol-G), estradiol, free estradiol, and sex hormone-binding globulin (SHBG) were measured at baseline, 3, and 12 months.

RESULTS

Exercisers trained a mean of 370 min.wk(-1) (102% of goal), with only two dropouts. Cardiopulmonary fitness (.VO(2max)) increased 10.8% in exercisers and decreased by 1.8% in controls (P < 0.001). DHT increased 14.5% in exercisers versus 1.7% in controls at 3 months (P = 0.04); at 12 months, it remained 8.6% above baseline in exercisers versus a 3.1% decrease in controls (P = 0.03). SHBG increased 14.3% in exercisers versus 5.7% in controls at 3 months (P = 0.04); at 12 months, it remained 8.9% above baseline in exercisers versus 4.0% in controls (P = 0.13). There were significant trends toward increasing DHT and SHBG, with greater increases in .VO(2max) at 3 and 12 months in exercisers. No statistically significant differences were observed for testosterone, free testosterone, 3alpha-Diol-G, estradiol, or free estradiol in exercisers versus controls.

CONCLUSIONS

A year-long, moderate-intensity aerobic exercise program increased DHT and SHBG, but it had no effect on other androgens in middle-aged to older men.

Risk of erectile dysfunction induced by arsenic exposure through well water consumption in Taiwan

BACKGROUND

Erectile dysfunction (ED) has a profound impact on the quality of life of many men. Many risk factors are associated with ED, such as aging, sex hormone levels, hypertension, cardiovascular diseases, and diabetes mellitus. Arsenic exposure could damage peripheral vessels and increase the risk of cardiovascular disease. However, the relationship between arsenic exposure and ED has seldom been evaluated.

OBJECTIVES

In this study we aimed to investigate whether exposure to arsenic enhances the risk of ED.

METHODS

We recruited 177 males >or= 50 years of age through health examinations conducted in three hospitals in Taiwan. We used a questionnaire (International Index of Erectile Function-5) to measure the level of erectile function. Sex hormones, including total testosterone and sex hormone-binding globulin, were determined by radioimmunoassay. We used another standardized questionnaire to collect background and behavioral information (e.g., cigarette smoking; alcohol, tea, or coffee drinking; and physical activity).

RESULTS

The prevalence of ED was greater in the arsenic-endemic area (83.3%) than in the non-arsenic-endemic area (66.7%). Subjects with arsenic exposure > 50 ppb had a significantly higher risk of developing ED than those with exposure <or= 50 ppb, after adjusting for age, cigarette smoking, diabetes mellitus, hypertension, and cardiovascular disease [odds ratio (OR) = 3.4]. Results also showed that the risk of developing severe ED was drastically enhanced by arsenic exposure (OR = 7.5), after adjusting for free testosterone and traditional risk factors of ED.

CONCLUSIONS

Results suggested that chronic arsenic exposure has a negative impact on erectile function.

Age-related changes in diurnal rhythms and levels of gonadotropins, testosterone, and inhibin B in male rhesus monkeys (Macaca mulatta)

Testosterone shows circadian rhythms in monkeys with low serum levels in the morning hours. The decline relies on a diminished frequency of LH pulses. Inhibin B shows no diurnal patterns. In elderly men, the diurnal rhythm of testosterone is blunted and inhibin levels fall. Here we explore whether aging exerts similar effects in the rhesus monkey. We collected blood samples from groups of young (6-9 yr) and old (12-16 yr) male rhesus monkeys at 20-min intervals for a period of 24 h under remote sampling via a venous catheter. We determined moment-to-moment changes in plasma levels of testosterone, FSH, and LH by RIA, and of inhibin B by ELISA. We found significant diurnal patterns of testosterone in both groups. The circadian rhythm in testosterone was enhanced in older monkeys. Testosterone levels and pulse frequencies dropped significantly below those of young monkeys during midday hours. Diminished pulse frequency of LH appeared to be responsible for the midday testosterone decrease in old monkeys, while LH and testosterone pulse frequency did not change in young monkeys at corresponding time points. Old monkeys showed extended periods of LH-pulse quiescence in the morning and midday hours. Inhibin B and FSH levels were generally lower in old monkeys compared with the young group, but neither inhibin B nor FSH showed circadian rhythms. We conclude from these data that old rhesus monkeys have a more prominent circadian rhythm of LH and testosterone resulting from an extended midday period of quiescence in the hypothalamus-pituitary-gonadal axis.

Testosterone replacement therapy

Hypgonadism has important adverse effects on the health and quality of life of affected men, but remains underdiagnosed in clinical practice. This article reviews the physiology, causes and diagnosis of hypogonadism and the potential benefits of treatment with testosterone replacement therapy.

Predictors of serum testosterone and DHEAS in African-American men

There are few reported data on biochemical and functional correlates of androgen levels in African-American men. This study aimed at reporting physical and biochemical correlates of serum total testosterone (total T), bioavailable testosterone (BT) and dehydroepiandrosterone-sulphate (DHEAS) levels in community-dwelling, African-American men aged 50-65 years. Home-based physical examinations and health status questionnaires were administered to randomly sampled men. Body composition (dual-energy X-ray absorptiometry), lower limb and hand-grip muscle strength, and neuropsychological functions were assessed. Levels of serum total T, BT, DHEAS, oestradiol (E2), adiponectin, leptin, triglycerides and glucose were measured. Multiple linear regression models were constructed to identify factors independently associated with androgen levels. DHEAS levels declined from age 50 to 65 years (p < 0.0001), but total T and BT levels remained constant. Independent of other associated factors, higher total T levels were associated with lower serum triglyceride levels (beta = -0.142, p = 0.049); higher BT was associated with better performance on the trail-making tests (TMT-B:TMT-A ratio: beta = -0.118, p = 0.024) and higher DHEAS levels were associated with lower adiponectin (beta = -0.293, p = 0.047) and higher mini-mental state examination (MMSE) score (beta = 0.098, p = 0.008). Multiple regression models predicted 21, 18 and 29% of variance in total T, BT and DHEAS, respectively. Higher total T levels were associated with serum metabolic markers, particularly lower triglycerides, whereas higher BT was associated with better cognitive and muscle function and DHEAS with lower adiponectin and higher MMSE scores.

The many faces of testosterone

Testosterone is more than a “male sex hormone”. It is an important contributor to the robust metabolic functioning of multiple bodily systems. The abuse of anabolic steroids by athletes over the years has been one of the major detractors from the investigation and treatment of clinical states that could be caused by or related to male hypogonadism. The unwarranted fear that testosterone therapy would induce prostate cancer has also deterred physicians form pursuing more aggressively the possibility of hypogonadism in symptomatic male patients. In addition to these two mythologies, many physicians believe that testosterone is bad for the male heart. The classical anabolic agents, 17-alkylated steroids, are, indeed, potentially harmful to the liver, to insulin action to lipid metabolism. These substances, however, are not testosterone, which has none of these adverse effects. The current evidence, in fact, strongly suggests that testosterone may be cardioprotective. There is virtually no evidence to implicate testosterone as a cause of prostate cancer. It may exacerbate an existing prostate cancer, although the evidence is flimsy, but it does not likely cause the cancer in the first place. Testosterone has stimulatory effects on bones, muscles, erythropoietin, libido, mood and cognition centres in the brain, penile erection. It is reduced in metabolic syndrome and diabetes and therapy with testosterone in these conditions may provide amelioration by lowering LDL cholesterol, blood sugar, glycated hemoglobin and insulin resistance. The best measure is bio-available testosterone which is the fraction of testosterone not bound to sex hormone binding globulin. Several forms of testosterone administration are available making compliance much less of an issue with testosterone replacement therapy.

Testosterone replacement therapy for older men

Despite intensive research on testosterone therapy for older men, important questions remain unanswered. The evidence clearly indicates that many older men display a partial androgen deficiency. In older men, low circulating testosterone is correlated with low muscle strength, with high adiposity, with insulin resistance and with poor cognitive performance. Testosterone replacement in older men has produced benefits, but not consistently so. The inconsistency may arise from differences in the dose and duration of testosterone treatment, as well as selection of the target population. Generally, studies reporting anabolic responses to testosterone have employed higher doses of testosterone for longer treatment periods and have targeted older men whose baseline circulating bioavailable testosterone levels were low. Most studies of testosterone replacement have reported anabolic that are modest compared to what can be achieved with resistance exercise training. However, several strategies currently under evaluation have the potential to produce greater anabolic effects and to do so in a safe manner. At this time, testosterone therapy can not be recommended for the general population of older men. Older men who are hypogonadal are at greater risk for the catabolic effects associated with a number of acute and chronic medical conditions. Future research is likely to reveal benefits of testosterone therapy for some of these special populations. Testosterone therapy produces a number of adverse effects, including worsening of sleep apnea, gynecomastia, polycythemia and elevation of PSA. Efficacy and adverse effects should be assessed frequently throughout the course of therapy.

The prevalence of and risk factors for androgen deficiency in aging Taiwanese men

INTRODUCTION

Androgen deficiency in aging men has attracted much medical interest. Most studies on androgen deficiency have been conducted in Caucasian populations, and data from other ethnicities are lacking.

AIM

To evaluate the prevalence of and risk factors for androgen deficiency and symptomatic androgen deficiency in Taiwanese men over 40 years old.

METHODS

From August 2007 to April 2008, a free health screening was conducted by a medical center in Kaohsiung, Taiwan, and 819 men participated in this health screening. All participants completed a health questionnaire, received a detailed physical examination, and blood samples were drawn between 8:00 and 12:00 am.

MAIN OUTCOME MEASURES

Serum total testosterone (TT), albumin, and sex hormone-binding globulin levels were measured. The level of free testosterone (FT) was calculated. Clinical symptoms of androgen deficiency were assessed using the Androgen Deficiency in the Aging Male (ADAM) questionnaire.

RESULTS

Seven hundred thirty-four men who met the inclusion criteria (mean age 57.4 +/- 6.7 years; range: 43-87 years) were included in this study. The prevalence of androgen deficiency was 24.1% based on the criterion of TT level < 300 ng/dL, and 16.6% based on the criterion of both TT < 300 ng/dL and FT < 5 ng/dL. The prevalence of symptomatic androgen deficiency was 12.0%. Both prevalence of androgen deficiency and symptomatic androgen deficiency increased with age. Older age, obesity, and diabetes mellitus were independent risk factors for androgen deficiency and symptomatic androgen deficiency.

CONCLUSIONS

In a sample of aging Taiwanese men, a substantial proportion had androgen deficiency and symptomatic androgen deficiency, and the prevalence increased with age. Older age, obesity, and diabetes mellitus were independent risk factors for androgen deficiency and symptomatic androgen deficiency. Those potentially modifiable risk factors like obesity and diabetes mellitus should be prevented to maintain normal testosterone levels during aging in men.

The paradox dividing testosterone deficiency symptoms and androgen assays: a closer look at the cellular and molecular mechanisms of androgen action

INTRODUCTION

Central to the diagnosis and treatment of testosterone deficiency syndrome in the adult male is the remarkable paradox that there is a very poor correlation between the characteristic symptoms and levels of serum androgens.

AIM

Because androgen deficiency can be associated with severe symptomatology, as well as diverse conditions such as coronary heart disease, diabetes, and metabolic syndrome, the aim was to present an evidence-based working hypothesis to resolve this confusing clinical paradox.

METHODS

A review of the possible mechanisms in testosterone deficiency syndrome was carried out, and a hypothesis to explain this paradox and associated problems in the diagnosis and clinical management of androgen deficiency was established on the basis of a review of the literature.

MAIN OUTCOME MEASURES

The mechanisms by which androgen deficiency could arise were studied at five different levels: 1. Impaired androgen synthesis or regulation. 2. Increased androgen binding. 3. Reduced tissue responsiveness. 4. Decreased androgen receptor activity. 5. Impaired transcription and translation.

RESULTS

As with insulin in maturity onset diabetes mellitus, there can be both insufficient production and variable degrees of resistance to the action of androgens operating at several levels in the body simultaneously, with these factors becoming progressively worse with aging, adverse lifestyle, other disease processes, and a wide range of medications.

CONCLUSIONS

Using this model, androgen deficiency can be redefined as an absolute or relative deficiency of androgens or their metabolites according to the needs of that individual at that time in his life. There are important ways in which the considerations raised by this hypothesis affect the etiology, terminology, diagnosis, and treatment of androgen-deficient states.

State of the Art Reviews: Male Menopause: Fact or Fiction?

The possible existence of a menopause-like process in aging men has been speculated, given certain age-related hormonal and other biological changes noted to occur. Specifically, a slow decline in serum testosterone levels has been reported to occur with normal male aging. Androgen deficiency, which may result from this process, could have an effect on various systems and physiologic parameters, including bone density, body composition, sexual function, and the cardiovascular system, thus significantly affecting health and quality-of-life issues in older men. There has been an increasing interest in evaluating the possible use of testosterone replacement in preventing some detrimental aspects of aging and age-related hypogonadism, as well as in the investigation of the potential adverse effects of this therapy on different target organs. It is the purpose of this review to summarize currently available information with regard to the changes in testosterone and other hormones in older men, discuss their possible clinical manifestations and relationship with other age-related changes, and provide an updated description of testosterone replacement therapy for older men, including its indications, formulations, and safety considerations.

Men's Attraction to Women's Bodies Changes Seasonally

Humans exhibit seasonal variation in hormone levels, behaviour, and perception. Here we show that men's assessments of women's attractiveness change also seasonally. In five seasons (from winter 2004 to winter 2005) 114 heterosexual men were asked to assess the attractiveness of the same stimuli: photos of a female with three different waist-to-hip ratios; photos of female breasts, and photos of average-looking faces of young women. For each season, the scores given to the stimuli of the same category (body shape, breast, and face) were combined. Friedman's test revealed significant changes for body shape and breast attractiveness assessments across the seasons, but no changes for face ratings. The highest scores for attractiveness were given in winter and the lowest in summer. We suggest that the observed seasonality is related to the well-known ‘contrast effect’. More frequent exposure to women's bodies in warmer seasons might increase men's attractiveness criteria for women's body shape and breasts.

Age-related alterations in pituitary and testicular functions in long-lived growth hormone receptor gene-disrupted mice

The somatotropic axis, GH, and IGF-I interact with the hypothalamic-pituitary-gonadal axis in health and disease. GH-resistant GH receptor-disrupted knockout (GHRKO) male mice are fertile but exhibit delayed puberty and decreases in plasma FSH levels, testicular content of LH, and prolactin (PRL) receptors, whereas PRL levels are elevated. Because the lifespan of GHRKO mice is much greater than the lifespan of their normal siblings, it was of interest to compare age-related changes in the hypothalamic-pituitary-gonadal axis in GHRKO and normal animals. Plasma IGF-I, insulin, PRL, LH, FSH, androstenedione and testosterone levels, and acute responses to GnRH and LH were measured in young (2-4 and 5-6 months of age) and old (18-19 and 23-26 months of age) male GHRKO mice and their normal siblings. Plasma IGF-I was not detectable in GHRKO mice. Plasma PRL levels increased with age in normal mice but declined in GHRKO males, and did not differ in old GHRKO and normal animals. Plasma LH responses to acute GnRH stimulation were attenuated in GHRKO mice but increased with age only in normal mice. Plasma FSH levels were decreased in GHRKO mice regardless of age. Plasma testosterone responses to LH stimulation were attenuated in old mice regardless of genotype, whereas plasma androstenedione responses were reduced with age only in GHRKO mice. Testicular IGF-I mRNA levels were normal in young and increased in old GHRKO mice, whereas testicular concentrations and total IGF-I levels were decreased in these animals. These findings indicate that GH resistance due to targeted disruption of the GH receptor gene in mice leads to suppression of testicular IGF-I levels, and modifies the effects of aging on plasma PRL levels and responses of the pituitary and testes to GnRH and LH stimulation. Plasma testosterone levels declined during aging in normal but not in GHRKO mice, and the age-related increase in the LH responses to exogenous GnRH was absent in GHRKO mice, perhaps reflecting a delay of aging in these remarkably long-lived animals.

Secular decline in male testosterone and sex hormone binding globulin serum levels in Danish population surveys

CONTEXT

Adverse secular trends in male reproductive health have been reported to be reflected in increased testicular cancer risk and decreased semen quality in more recently born men. These secular trends may also be reflected by changes in Leydig cell function.

OBJECTIVE

The objective of the study was to examine whether an age-independent time trend in male serum testosterone levels exists.

DESIGN AND SETTING

Testosterone and SHBG were analyzed in 5350 male serum samples from four large Danish population surveys conducted in 1982-1983, 1986-1987, 1991-1992, and 1999-2001. Free testosterone levels were calculated. The effects of age, year of birth, and time period on hormone levels were estimated in a general linear statistical model.

MAIN OUTCOME MEASURES

Testosterone, SHBG, and calculated free testosterone levels in Danish men in relation to age, study period, and year of birth were measured.

RESULTS

Serum testosterone levels decreased and SHBG levels increased with increasing age. In addition to this expected age effect, significant secular trends in testosterone and SHBG serum levels were observed in age-matched men with lower levels in the more recently born/studied men. No significant age-independent effect was observed for free testosterone. Adjustment for a concurrent secular increase in body mass index reduced the observed cohort/period-related changes in testosterone, which no longer were significant. The observed cohort/period-related changes in SHBG levels remained significant after adjustment for body mass index.

CONCLUSIONS

The observed age-independent changes in SHBG and testosterone may be explained by an initial change in SHBG levels, which subsequently lead to adjustment of testosterone at a lower level to sustain free testosterone levels.

Intraindividual variation in levels of serum testosterone and other reproductive and adrenal hormones in men

BACKGROUND

Estimates of intraindividual variation in hormone levels provide the basis for interpreting hormone measurements clinically and for developing eligibility criteria for trials of hormone replacement therapy. However, reliable systematic estimates of such variation are lacking.

OBJECTIVE

To estimate intraindividual variation of serum total, free and bioavailable testosterone (T), dihydrotestosterone (DHT), SHBG, LH, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulphate (DHEAS), oestrone, oestradiol and cortisol, and the contributions of biological and assay variation to the total.

DESIGN

Paired blood samples were obtained 1-3 days apart at entry and again 3 months and 6 months later (maximum six samples per subject). Each sample consisted of a pool of equal aliquots of two blood draws 20 min apart.

STUDY PARTICIPANTS

Men aged 30-79 years were randomly selected from the respondents to the Boston Area Community Health Survey, a study of the health of the general population of Boston, MA, USA. Analysis was based on 132 men, including 121 who completed all six visits, 8 who completed the first two visits and 3 who completed the first four visits.

MEASUREMENTS

Day-to-day and 3-month (long-term) intraindividual standard deviations, after transforming measurements to logarithms to eliminate the contribution of hormone level to intraindividual variation.

RESULTS

Biological variation generally accounted for more of total intraindividual variation than did assay variation. Day-to-day biological variation accounted for more of the total than did long-term biological variation. Short-term variability was greater in hormones with pulsatile secretion (e.g. LH) than those that exhibit less ultradian variation. Depending on the hormone, the intraindividual standard deviations imply that a clinician can expect to see a difference exceeding 18-28% about half the time when two measurements are made on a subject. The difference will exceed 27-54% about a quarter of the time.

CONCLUSIONS

Given the level of intraindividual variability in hormone levels found in this study, one sample is generally not sufficient to characterize an individual's hormone levels but collecting more than three is probably not warranted. This is true for clinical measurements and for hormone measurements used to determine eligibility for a clinical trial of hormone replacement therapy.

Androgen therapy for loss of desire in women: is the benefit worth the breast cancer risk?

OBJECTIVE

To contrast the limited evidence that androgen therapy is an effective treatment for low sexual desire in women with the extensive literature suggesting that androgens promote breast cancer.

DESIGN

Evidence from population studies of women is reviewed on the association between endogenous androgen levels and sexual function or satisfaction. Recent randomized trials of testosterone therapy for low desire are critiqued in terms of methodology and generalizability. Research on endogenous testosterone levels and breast cancer risk in both premenopausal and postmenopausal women is summarized, as are recent studies of androgenic hormonal therapy and breast cancer risk.

SETTING

Literature review.

PATIENT(S)

Not applicable.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

Not applicable.

RESULT(S)

Endogenous androgen levels are not correlated with sexual desire in population-based studies of aging women. Factors that are strongly associated with low desire include pain with sexual activity, emotional distress, life stress, and relationship conflict. The efficacy of testosterone therapy for women's desire problems is modest. Expectancy effects were not adequately controlled in randomized trials. Epidemiological findings agree that higher endogenous serum androgen levels confer increased breast cancer risk both before and after menopause. Androgenic hormonal replacement regimens also increase the risk of breast cancer.

CONCLUSION(S)

Testosterone supplementation should not be prescribed to women with low sexual desire unless long-term studies can demonstrate its efficacy and safety. Treatments for low sexual desire in women should address its common correlates: relationship distress, emotional distress, and dyspareunia.

Lack of seasonal variation in serum sex hormone levels in middle-aged to older men in the Boston area

CONTEXT

Previous studies of seasonal variation of testosterone and other hormones in men have produced mixed results regarding the number and timing of peaks and nadirs and whether hormones vary seasonally at all. Wide variation in study designs, sample sizes, analytical methods, and characteristics of the study populations may account for the heterogeneity of results.

OBJECTIVE

The objective of the study was to determine whether serum total, free, and bioavailable testosterone, dihydrotestosterone, SHBG, LH, dehydroepiandrosterone, dehydroepiandrosterone sulfate, estrone, estradiol, and cortisol vary seasonally in men.

DESIGN

Two blood samples were drawn 1-3 d apart at study entry and again 3 and 6 months later (maximum six samples per subject). Hormone levels 1-3 d apart were averaged to reduce short-term intrasubject variation.

SETTING

The study population consisted of a community-dwelling population (Boston, MA).

STUDY PARTICIPANTS

One hundred thirty-four men 30-79 yr old were randomly selected from the respondents to the Boston Area Community Health Survey. One hundred twenty-one men who completed all six visits were included in the analysis.

MAIN OUTCOME MEASURES

In a repeated-measures analysis, 3-month change in hormone levels, measured twice per subject, and in a sinusoidal nonlinear regression with random subject effects, average hormone level in samples 1-3 d apart were measured.

RESULTS

Aside from cortisol, no evidence of seasonal variation in hormone levels was found. The amplitude of seasonal variation was much smaller than total intraindividual variation for all hormones considered.

CONCLUSIONS

Seasonal variation is likely an unimportant source of variation clinically and in epidemiological studies of hormone levels.

Prevalence of symptomatic androgen deficiency in men

CONTEXT

Despite recognition that androgen deficiency in men should be defined according to biochemical and clinical criteria, most prevalence estimates are based on low testosterone levels alone.

OBJECTIVE

The objective of this study was to examine the association between symptoms of androgen deficiency and low total and calculated free testosterone levels and estimate the prevalence of symptomatic androgen deficiency in men.

DESIGN

This study was a population-based, observational survey.

PARTICIPANTS

A total of 1,475 Black, Hispanic, and white men, between the ages of 30-79 yr, with complete data on testosterone, SHBG, and symptoms of androgen deficiency, and who are not taking medications that impact sex steroid levels were randomly selected from the Boston Area Community Health Survey.

OUTCOME

Outcomes were measured as symptomatic androgen deficiency, defined as low total (<300 ng/dl) and free (<5 ng/dl) testosterone plus presence of low libido, erectile dysfunction, osteoporosis or fracture, or two or more of following symptoms: sleep disturbance, depressed mood, lethargy, or diminished physical performance.

RESULTS

Mean age of the sample was 47.3 +/- 12.5 yr. Approximately 24% of subjects had total testosterone less than 300 ng/dl, and 11% of subjects had free testosterone less than 5 ng/dl. Prevalence of symptoms were as follows: low libido (12%), erectile dysfunction (16%), osteoporosis/fracture (1%), and two or more of the nonspecific symptoms (20%). Low testosterone levels were associated with symptoms, but many men with low testosterone levels were asymptomatic (e.g. in men 50+ yr, 47.6%). Crude prevalence of symptomatic androgen deficiency was 5.6% (95% confidence interval: 3.6%, 8.6%), and was not significantly related to race and ethnic group. Prevalence was low in men less than 70 yr (3.1-7.0%) and increased markedly with age to 18.4% among 70 yr olds. Projection of these estimates to the year 2025 suggests that there will be as many as 6.5 million American men ages 30-79 yr with symptomatic androgen deficiency, an increase of 38% from 2000 population estimates.

CONCLUSIONS

Prevalence of symptomatic androgen deficiency in men 30 and 79 yr of age is 5.6% and increases substantially with age. The aging of the U.S. male population will cause a large increase in the burden of symptomatic androgen deficiency. Future work should address the clinical significance of low testosterone levels in asymptomatic men.

Determination of bioavailable testosterone [non sex hormone binding globulin (SHBG)-bound testosterone] in a population of healthy French men: influence of androstenediol on testosterone binding to SHBG

BACKGROUND

Bioavailable testosterone (BT) is measured [assayed BT (aBT)] or calculated (cBT) in the diagnosis of hypogonadism in men. The cBT depends, however, on the values of the association constants of total testosterone (TT) for sex hormone-binding globulin (SHBG; K(s)) and albumin (K(a)), and its use therefore remains controversial.

METHODS

In 503 selected, untreated healthy men, 20-74 years old, we measured TT, dihydrotestosterone (DHT), and androstenediol (5-diol) by GC-MS, SHBG by RIA, and BT after ammonium sulfate precipitation or by calculation according to the law of mass action.

RESULTS

A slight decrease in TT, significant decreases in BT and 5-diol, no variation in DHT, and an increase in SHBG were observed with age. In young males (< or = 39 years), the lower normal limits were between 2.30 and 2.72 nmol/L for aBT and 8.50 nmol/L for TT. For K(s) = 1 x 10(9) L/mol and K(a) = 3.6 x 10(4) L/mol, the lower cBT limit was found to be 2-fold higher than for aBT. With optimized K(s) = 1.9 x 10(9) L/mol and K(a) = 2.45 x 10(4) L/mol, cBT values close to aBT were obtained. When 5-diol was included in the model as a competitive SHBG inhibitor, the correlation between cBT and aBT was better and the cBT:aBT ratios vs 5-diol were less biased.

CONCLUSION

Lower normal serum aBT concentration in normal men appears to be between 2.30 and 2.72 nmol/L. Much higher serum cBT concentrations are associated with use of different association constants that may be inappropriate. When using the optimized binding constants, taking age-related 5-diol values into consideration slightly improves prediction of cBT.

Steroid hormones and carcinogenesis of the prostate: the role of estrogens

Androgens have long been known to be the major sex hormones that target the prostate during development, maturation, and carcinogenesis. It is now apparent that estrogens, both those synthesized by the body as well as those from our environment, also target the prostate during all stages of development. Little is known about the mechanisms involved in estrogen stimulation of carcinogenesis and less is known about how to prevent or treat prostate cancer through estrogenic pathways. To better understand how estrogens mediate their carcinogenic effects, the respective roles of estrogen receptor (ER)-alpha and ER-beta must be elucidated in the epithelial and stromal cells that constitute the prostate. Lastly, the significance of ER signaling during various ontogenic periods must be determined. Answers to these questions will further our understanding of the mechanisms of estrogen/ER signaling and will serve as a basis for chemopreventive and/or chemotherapeutic strategies for prostate cancer.

Prevalence and consequences of androgen deficiency in young male cancer survivors in a controlled cross-sectional study

BACKGROUND

Testosterone replacement in hypogonadal males improves body composition, sexual function, and health-related quality of life. Male cancer survivors are at risk of androgen deficiency; however, when and in whom testosterone should be replaced remain unanswered questions.

OBJECTIVE

The aim of our study was to define the prevalence of androgen deficiency in this patient group through assessment of testosterone levels and related measures.

DESIGN

This was a cross-sectional, observational study of cases and controls. We recruited 176 cancer survivors and 213 controls, aged 25-45 yr.

RESULTS

Of cancer survivors, 97% had received chemotherapy and 40% radiotherapy. Cancer survivors had lower total testosterone (tT) levels than controls (mean difference 2.67 nmol/liter; 95% confidence interval 1.58-3.76; P = 0.003), and 24 of 176 (13.6%; 95% confidence interval 9.3-19.5) had a tT less than 10 nmol/liter, which was less than 2.5% centile for controls. Cancer survivors had a greater fat mass, higher fasting insulin and glucose levels, increased fatigue, and reduced sexual function and health-related quality of life. In both cohorts, the tT correlated negatively with insulin levels and negatively with body fat mass; however, the difference in tT between them was independent of fat mass. We measured tT and SHBG and calculated bioavailable testosterone. The changes in calculated bioavailable testosterone were similar to tT.

CONCLUSIONS

A significant proportion of young male cancer survivors had a frankly low tT associated with an increased fat mass and insulin level compared with controls. These factors would be predicted to improve in response to testosterone replacement therapy and provide a powerful argument for an interventional study of testosterone therapy in young male cancer survivors.

The validity of androgen assays

Problems in the measurement of androgens and in interpreting results have been reviewed and classified as follows: PREANALYTICAL FACTORS: The exact sampling conditions in relation to circadian and seasonal variations, diet, alcohol, physical activity and posture.

PHYSIOLOGICAL AND MEDICAL FACTORS

Androgen levels vary according to the patient's general health, stress, sexual activity and smoking habits. Analytical variables. Sample preservation and storage variables are often unknown. The different androgen assays used have widely differing accuracy and precision and are subject to large inter-laboratory variation, which especially in women and children can render the results of routinely available direct immunoassays meaningless.

INTERPRETATION OF RESULTS

Laboratory reference ranges vary widely, largely independent of methodology, and fail to take into account the log-normal distribution of androgen values, causing errors in clinical diagnosis and treatment. Other unknowns are antagonists such as SHBG, estrogens, catecholamines, cortisol, and anti-androgens. As well as age, androgen receptor polymorphisms play a major role in regulating androgen levels and resistance to their action.

CONCLUSIONS

Though laboratory assays can support a diagnosis of androgen deficiency in men, they should not be used to exclude it. It is suggested that there needs to be greater reliance on the history and clinical features, together with careful evaluation of the symptomatology, and where necessary a therapeutic trial of androgen treatment given.

Effect of 2 years of testosterone replacement on insulin secretion, insulin action, glucose effectiveness, hepatic insulin clearance, and postprandial glucose turnover in elderly men

OBJECTIVE

We sought to determine whether, and if so the mechanism by which, testosterone replacement improves carbohydrate tolerance.

RESEARCH DESIGN AND METHODS

Fifty-five elderly men with relative testosterone deficiency ingested a labeled mixed meal and underwent a frequently sampled labeled intravenous glucose tolerance test before and after either placebo or treatment with testosterone patch (5 mg/day) for 2 years.

RESULTS

Despite restoring bioavailable testosterone to values observed in young men, the change (24 months minus baseline values) in fasting and postprandial glucose, insulin, and C-peptide concentrations and meal appearance, glucose disposal, and endogenous glucose production were virtually identical to those observed after 2 years of placebo. The change over time in insulin and C-peptide concentrations post-intravenous glucose injection also did not differ. Furthermore, the change over time in insulin action and glucose effectiveness (measured with the unlabeled and labeled "oral" and "intravenous" minimal models), as well as insulin secretion and hepatic insulin clearance (measured with the C-peptide model), did not differ in the testosterone and placebo groups.

CONCLUSIONS

We conclude that 2 years of treatment with testosterone in elderly men does not improve carbohydrate tolerance or alter insulin secretion, insulin action, glucose effectiveness, hepatic insulin clearance, or the pattern of postprandial glucose metabolism. Thus, testosterone deficiency is unlikely the cause of the age-associated deterioration in glucose tolerance commonly observed in elderly men.

Androgen regulation of beta-amyloid protein and the risk of Alzheimer's disease

Advancing age is the most significant risk factor for the development of Alzheimer's disease (AD), however the age-related changes that underlie this effect remain unclear. In men, one normal consequence of aging is a robust decline in circulating and brain levels of the sex steroid hormone testosterone. Testosterone depletion leads to functional impairments and increased risk of disease in androgen-responsive tissues throughout the body, including brain. In this review we discuss the relationship between age-related testosterone depletion and the development of AD. Specifically, we focus on androgen regulation of beta-amyloid protein (Abeta), the accumulation of which is a key initiating factor in AD pathogenesis. Emerging data suggest that the regulatory actions of androgens on both Abeta and the development of AD support consideration of androgen therapy for the prevention and treatment of AD.

Transcriptional profiling of testosterone-regulated genes in the skeletal muscle of human immunodeficiency virus-infected men experiencing weight loss

CONTEXT

HIV-associated wasting and weight loss remain clinically significant concerns even in the era of potent antiretroviral therapy. Although androgen treatment increases muscle mass, the cell-intrinsic mechanisms engaged remain poorly understood.

OBJECTIVE

This study was an unbiased approach to identify expression profiles associated with testosterone treatment using genome-wide microarray analysis of skeletal muscle biopsies.

DESIGN, SETTING, AND PARTICIPANTS

Forty-four HIV-positive men with weight loss were randomized to receive either 300 mg testosterone enanthate or placebo injections im weekly for 16 wk. Muscle biopsies were obtained at baseline and on treatment d 14. A subset of specimens was chosen for microarray analysis, with changes in selected genes confirmed by real-time PCR, Western blot analysis, and in vitro culture of muscle precursor cells.

RESULTS

Significantly greater gains in body mass (+2.05 and -1.07 kg, respectively; P = 0.003) and lean body mass by dual-energy x-ray absorptiometry (2.93 vs. 0.35 kg, respectively; P = 0.003) were observed in subjects treated with testosterone compared with placebo. Microarray analysis revealed up-regulation in genes involved in myogenesis and muscle protein synthesis, immune regulation, metabolic pathways, and chromatin remodeling. Representative genes were confirmed by real-time PCR and protein expression studies. In an independent analysis, gene networks that differentiate healthy young men from older men with sarcopenia had substantial overlap with those activated by testosterone treatment.

CONCLUSIONS

These data provide new insights into the mechanisms of androgen action and have implications for both development of muscle biomarkers and anabolic therapies for wasting and sarcopenia.

Salivary cortisol and DHEA levels in the Korean population: age-related differences, diurnal rhythm, and correlations with serum levels

PURPOSE

The primary objective of this study was to examine the changes of basal cortisol and DHEA levels present in saliva and serum with age, and to determine the correlation coefficients of steroid concentrations between saliva and serum. The secondary objective was to obtain a standard diurnal rhythm of salivary cortisol and DHEA in the Korean population.

MATERIALS AND METHODS

For the first objective, saliva and blood samples were collected between 10 and 11 AM from 359 volunteers ranging from 21 to 69 years old (167 men and 192 women). For the second objective, four saliva samples (post-awakening, 11 AM, 4 PM, and bedtime) were collected throughout a day from 78 volunteers (42 women and 36 men) ranging from 20 to 40 years old. Cortisol and DHEA levels were measured using a radioimmunoassay (RIA).

RESULTS

The morning cortisol and DHEA levels, and the age- related steroid decline patterns were similar in both genders. Serum cortisol levels significantly decreased around forty years of age (p < 0.001, when compared with people in their 20s), and linear regression analysis with age showed a significant declining pattern (slope=-2.29, t=-4.297, p < 0.001). However, salivary cortisol levels did not change significantly with age, but showed a tendency towards decline (slope=-0.0078, t=-0.389, p=0.697). The relative cortisol ratio of serum to saliva was 3.4-4.5% and the ratio increased with age (slope=0.051, t=3.61, p < 0.001). DHEA levels also declined with age in saliva (slope=-0.007, t=-3.76, p < 0.001) and serum (slope=-0.197 t=-4.88, p < 0.001). In particular, DHEA levels in saliva and serum did not start to significantly decrease until ages in the 40s, but then decreased significantly further at ages in the 50s (p < 0.001, when compared with the 40s age group) and 60s (p < 0.001, when compared with the 50 age group). The relative DHEA ratio of serum to saliva was similar throughout the ages examined (slop=0.0016, t=0.344, p=0.73). On the other hand, cortisol and DHEA levels in saliva reflected well those in serum (r=0.59 and 0.86, respectively, p < 0.001). The highest salivary cortisol levels appeared just after awakening (about two fold higher than the 11 AM level), decreased throughout the day, and reached the lowest levels at bedtime (p < 0.001, when compared with PM cortisol levels). The highest salivary DHEA levels also appeared after awakening (about 1.5 fold higher than the 11 AM level) and decreased by 11 AM (p < 0.001). DHEA levels did not decrease further until bedtime (p=0.11, when compared with PM DHEA levels).

CONCLUSION

This study showed that cortisol and DHEA levels change with age and that the negative slope of DHEA was steeper than that of cortisol in saliva and serum. As the cortisol and DHEA levels in saliva reflected those in serum, the measurement of steroid levels in saliva provide a useful and practical tool to evaluate adrenal functions, which are essential for clinical diagnosis.

Discovery of potent and muscle selective androgen receptor modulators through scaffold modifications

A novel series of imidazolin-2-ones were designed and synthesized as highly potent, orally active and muscle selective androgen receptor modulators (SARMs), with most of the compounds exhibiting low nM in vitro potency in androgen receptor (AR) binding and functional assays. Once daily oral treatment with the lead compound 11a (AR Ki = 0.9 nM, EC50 = 1.8 nM) for 14 days induced muscle growth with an ED50 of 0.09 mg/kg, providing approximately 50-fold selectivity over prostate growth in an orchidectomized rat model. Pharmacokinetic studies in rats demonstrated that the lead compound 11a had oral bioavailability of 65% and a plasma half-life of 5.5 h. On the basis of their preclinical profiles, the SARMs in this series are expected to provide beneficial anabolic effects on muscle with minimal androgenic effects on prostate tissue.

Body composition, metabolic syndrome and testosterone in ageing men

The ageing process in men is marked by changes in body composition (loss of fat-free mass (FFM) and skeletal muscle, and gain in fat mass (FM)) and is associated with a decline in serum testosterone. Correlations between these aspects of ageing and the acknowledged role of exogenous testosterone in reversing the loss of FFM and gain in FM seen in adult men with congenital or acquired hypoandrogenism have led to the hypothesis that testosterone therapy in ageing men will result in favourable changes in body composition and may improve metabolic status and/or cardiovascular risk. Data from randomized controlled trials of testosterone therapy in ageing men addressing the endpoints of body composition and components of the metabolic syndrome and cardiovascular risk factors are reviewed, and the impact of the increasing prevalence of obesity on these relationships is considered.

Relationship between the Saint Louis University ADAM questionnaire and sexual hormonal levels in a male outpatient population over 50 years of age

OBJECTIVES

To determine the relationship between the ADAM questionnaire and the sexual hormonal levels in a male population older than 50 yr, and to know the predictive capacity of this questionnaire with regard to biochemical hypogonadism in the ageing male.

METHODS

A prospective study was carried out on 230 Spanish men. Patients were evaluated by clinical history. The ADAM questionnaire and the Yesavage's Geriatric Depression Scale were completed by each patient. Blood tests were performed including total testosterone, SHBG, free testosterone (FT), dehidroepiandrosterone sulfate (DHEA-S), androstenedione, 17-beta-estradiol, FSH, LH, and prolactin. The relationship between positive ADAM questionnaire and age, clinical and sociodemographic backgrounds, and hormone levels was analysed by means of uni- and multivariate tests. The capacity of the ADAM questionnaire to predict biochemical hypogonadism was determined with a chi-square test.

RESULTS

ADAM questionnaire (excluding men with positive Yesavage's Scale) was positive in 140 patients (67.9%). With respect to clinical backgrounds, diabetes mellitus and age had a significant relationship with an ADAM-positive questionnaire. With respect to hormones, FT and DHEA-S levels were significantly lower when the ADAM questionnaire was positive. In the multivariate analysis, age, FT, and diabetes were independently related to an ADAM-positive questionnaire. Prevalence of biochemical hypogonadism (FT<0.228 nmol/l) was 24.6%. The ADAM test had a sensitivity of 84.0% and a specificity of 36.6% to detect biochemical hypogonadism.

CONCLUSIONS

FT is inversely related to the ADAM-positive questionnaire, independently of age. The ADAM questionnaire is a valid test to detect hypogonadism but has low specificity.

A retrospective analysis on biochemical parameters, cardiovascular risk and cardiomyopathy in elderly acromegalic patients

This analytical, observational, retrospective, case-control study was designed to describe clinical presentation, biochemical disease severity, presence, and severity of metabolic and cardiovascular complications in patients diagnosed as having acromegaly at 60 yr or older (no.=57) as compared to sex- and age-matched healthy controls. Patients and controls underwent a complete endocrine, metabolic, and cardiovascular check-up. The age at diagnosis was equally distributed between 60 to 75 yr while only a minority of the patients (5.3%) was diagnosed after 75 yr. Median GH and IGF-I levels were 15 microg/l and 557 microg/l. The prevalence of microadenomas, enclosed macroadenomas, and extrasellar/invasive macroadenomas was 30%, 49%, and 21%, respectively. All patients had joint complaints and goiter (euthyroid in 65% and pre-toxic/toxic in 35%), 82% had hypertension, 58% diabetes and 54% had both. As compared to controls, a higher number of patients were receiving treatment with anti-arrhythmiacs (p=0.033), anti-aggregants (p=0.013), levothyroxine (p=0.015), and metformin (p=0.022). Nevertheless, the patients had higher systolic and diastolic blood pressure, heart rate, left ventricular mass index, lipids, glucose and insulin levels as well as percent function of beta cells than controls. In conclusion, the high prevalence of systemic complications makes elderly acromegalics more susceptible than controls to cardiovascular events. We suggest that an accurate clinical check-up and, possibly, a more aggressive treatment of hypertension and diabetes are required in elderly acromegalics.

Age-related changes in seminal polymorphonuclear elastase in men with asymptomatic inflammation of the genital tract

AIM

To investigate age-related inflammatory events in the male genital tract.

METHODS

In a total of 4265 randomly collected patients attending the andrological outpatient clinic of the Center for Dermatology and Andrology, University of Giessen, Germany, ejaculate volume, pH-value, sperm concentration, total and progressive sperm motility, concentration of polymorphonuclear (PMN) elastase, number of peroxidase-positive cells and fructose were measured and correlated with patient's age.

RESULTS

While ejaculate volume, motility and fructose all correlated negatively with age, sperm concentration, PMN elastase and the pH-value showed a positive correlation. The prevalence of male genital tract inflammation (as defined by PMN elastase > 250 ng/mL) and its severity increased significantly. PMN elastase did not correlate with sperm motility. Fructose as a marker of seminal vesicle function showed a significant negative relationship with the PMN elastase levels, the number of peroxidase-positive cells and sperm motility.

CONCLUSION

The significant increases of PMN-elastase levels as marker of male genital tract inflammation in older men appear to be indicative of age-related changes in local immunoregulatory mechanisms. Because there is no association of PMN elastase with sperm motility, a direct inhibitory effect of this enzyme can be excluded.

Age-Related Structural and Metabolic Changes in the Pelvic Reproductive End Organs

In this work, we provide preliminary data and a review of the literature regarding normal structural and functional changes that occur in the aging uterus, ovary, testicle, and prostate gland. It is expected that such knowledge will help physicians to distinguish physiologic changes from pathologic changes at an early stage. We retrospectively reviewed pelvic magnetic resonance imaging (MRI) scans of 131 female and 79 male subjects ages 13 to 86 years to determine changes in volume of the uterus, ovary, and prostate gland with age. Scrotal ultrasound examinations of 150 male subjects ages 0 to 96 years also were analyzed retrospectively to determine changes in testicular volume with age. In addition, (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG-PET) scans of 145 male subjects ages 11 to 90 years were analyzed retrospectively to assess for changes in maximum standardized uptake value (SUV(max)) of the testicles with age. The uterus had a mean volume of 38.55 +/- 3.68 cm(3) at 17 to 19 years of age, increased to a peak volume of 71.76 +/- 19.81 cm(3) between 35 to 40 years, and then declined to 24.02 +/- 8.11 cm(3) by the eighth decade of life. The maximal ovarian volume per subject maintained a relatively stable size in early life, measuring 9.46 +/- 3.25 cm(3) during the second decade of life, 8.46 +/- 3.32 cm(3) in the mid-fourth decade of life, and 7.46 +/- 3.33 cm(3) at 45 years of age, after which it declined to 4.44 +/- 2.02 cm(3) by the late fifth decade of life. The ovaries were not identifiable on MRI in subjects beyond the sixth decade of life. The volume of the prostate increased from 23.45 +/- 6.20 cm(3) during the second decade of life to 47.5 +/- 41.59 cm(3) by the late eighth decade of life; the central gland of the prostate increased from 9.96 +/- 3.99 cm(3) to 29.49 +/- 28.88 cm(3) during the same age range. Mean testicular volume was 11.2 +/- 5.9 cm(3). Testicular volume increased with age from birth to 25 years. After age 25, there was a significant decline in the testicular volume. The mean SUV(max) for the testicles was 1.9 +/- 0.5. Testicular metabolic activity demonstrated an increasing trend until the age of 35 years. A plateau in SUV(max) was observed after the age of 35 years until the age of 65 years. A slight decrease in SUV(max) was observed after the age of 65 years. The pelvic structures of men and women change both structurally and functionally over the lifespan, and such changes can be quantified using ultrasound, MRI, and (18)F-FDG-PET.

Hormonal regulation of longevity in mammals

Multiple biological and environmental factors impact the life span of an organism. The endocrine system is a highly integrated physiological system in mammals that regulates metabolism, growth, reproduction, and response to stress, among other functions. As such, this pervasive entity has a major influence on aging and longevity. The growth hormone, insulin-like growth factor-1 and insulin pathways have been at the forefront of hormonal control of aging research in the last few years. Other hormones, including those from the thyroid and reproductive system have also been studied in terms of life span regulation. The relevance of these hormones to human longevity remains to be established, however the evidence from other species including yeast, nematodes, and flies suggest that evolutionarily well-conserved mechanisms are at play and the endocrine system is a key determinant.

Age-Associated Discrepancy between Measured and Calculated Bioavailable Testosterone in Men

Background: Bioavailable testosterone (BT) concentration is considered the best marker for evaluating testicular function in men. The decrease of BT in older men is more pronounced than the decrease in total testosterone because of the parallel increase in sex hormone–binding globulin (SHBG) concentrations. Measurement of BT is therefore crucial for the diagnosis of hypoandrogenism in the aging male population.

Methods: We compared BT concentrations measured by a specific RIA after ammonium sulfate precipitation (BTmeas) with those obtained by theoretical calculations (BTcal) in plasma samples from 694 young men (14 to 49 years old) and 51 older men (50 to 81 years old). We based theoretical calculations on Vermeulen’s simplified mass equation using total testosterone and SHBG concentrations.

Results: BTcal and BTmeas correlated significantly in young (Pearson r = 0.87) and aging (r = 0.89) men, but the BTcal:BTmeas ratio differed markedly between the 2 groups (2.28 vs 3.48; P &lt;0.001).

Conclusions: In men, there is an age-associated discrepancy between calculated and measured BT concentrations. We suggest some hypotheses for the discrepancy, but additional studies will be performed to finally elucidate this difference in results and to determine the most appropriate method for BT measurements in older men.

Prevalence of hypogonadism in males aged at least 45 years: the HIM study

The Hypogonadism in Males study estimated the prevalence of hypogonadism [total testosterone (TT) < 300 ng/dl] in men aged > or = 45 years visiting primary care practices in the United States. A blood sample was obtained between 8 am and noon and assayed for TT, free testosterone (FT) and bioavailable testosterone (BAT). Common symptoms of hypogonadism, comorbid conditions, demographics and reason for visit were recorded. Of 2162 patients, 836 were hypogonadal, with 80 receiving testosterone. Crude prevalence rate of hypogonadism was 38.7%. Similar trends were observed for FT and BAT. Among men not receiving testosterone, 756 (36.3%) were hypogonadal; odds ratios for having hypogonadism were significantly higher in men with hypertension (1.84), hyperlipidaemia (1.47), diabetes (2.09), obesity (2.38), prostate disease (1.29) and asthma or chronic obstructive pulmonary disease (1.40) than in men without these conditions. The prevalence of hypogonadism was 38.7% in men aged > or = 45 years presenting to primary care offices.

Measuring gonadotropins is of limited value in detecting hypogonadism in ageing men: the Tromsø study

Testosterone levels decrease with age. The mechanisms responsible for the age-related decrease in testosterone concentration are still being debated, and probably involve all three levels of the hypothalamo-pituitary-testicular axis. Luteinizing hormone (LH) concentration is often measured in combination with testosterone, but its value is questionable when considering the testosterone levels of older men. The objective of the present study was to examine the associations of endogenous gonadotropin and testosterone levels both in a cross-sectional cohort of 3447 men participating in the fifth Tromsø study and longitudinally in a cohort of 1352 men participating in both the fourth and the fifth Tromsø study. Total testosterone, LH, follicle-stimulating hormone and sex hormone-binding globulin levels were measured with immunoassay while free testosterone levels were calculated. Total testosterone and LH were independently and positively associated in the cross-sectional analyses (p < 0.001). In the longitudinal study, however, LH levels did not predict changes in total and free testosterone levels. Thus, in clinical practice, measuring gonadotropins seems to be of limited value in detecting hypogonadism in ageing men.