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

OBJECTIVE: Serum testosterone measurements in clinical practice mostly utilize "direct" (non-extraction) immunoassays which have method-specific bias due to steroid cross-reactivity and nonspecific matrix artifacts. Although more accurate, sensitive, and specific liquid chromatography-mass spectrometry (LCMS) dominates in clinical research, the within-person variability of serum testosterone in healthy men using LCMS measurement is not reported. DESIGN: Longitudinal multi-sampling observational study of men in excellent health over 3 months. METHODS: Elite healthy men (n = 325) over 40 years of age in excellent, asymptomatic health provided 9 blood samples over 3 months with serum testosterone, dihydrotestosterone (DHT), estradiol (E2), and estrone (E1) measured by validated LCMS with conventional biochemical and anthropometric variables. RESULTS: Quantitative estimates of within-person variability within day and between day, week, month, and quarter were stable other than an increase due to fasting. The androgen biomarkers most sensitive to age and testosterone among widely used biochemical and anthropometric variables in middle-aged and older men were identified. CONCLUSIONS: This study provides estimates of variability in serum testosterone and the best androgen biomarkers that may prove useful for future studies of androgen action in male ageing.

Recovery of male reproductive endocrine function after ceasing prolonged testosterone undecanoate injections.

CONTEXT: The time course of male reproductive hormone recovery after stopping injectable testosterone undecanoate (TU) treatment is not known. OBJECTIVE: The aim of this study was to investigate the rate, extent, and determinants of reproductive hormone recovery over 12 months after stopping TU injections. MATERIALS AND METHODS: Men (n = 303) with glucose intolerance but without pathologic hypogonadism who completed a 2-year placebo (P)-controlled randomized clinical trial of TU treatment were recruited for further 12 months while remaining blinded to treatment. Sex steroids (testosterone (T), dihydrotestosterone, oestradiol, oestrone) by liquid chromatography-mass sprectometry, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and sex hormone-binding globulin (SHBG) by immunoassays and sexual function questionnaires (Psychosexual Diary Questionnaire, International Index of Erectile Function, and short form survey (SF-12)) were measured at entry (3 months after the last injection) and 6, 12, 18, 24, 40, and 52 weeks later. RESULTS: In the nested cohort of TU-treated men, serum T was initially higher but declined at 12 weeks remaining stable thereafter with serum T and SHBG at 11 and 13%, respectively, lower than P-treated men. Similarly, both questionnaires showed initial carry-over higher scores in T-treated men but after 18 weeks showed no difference between T- and P-treated men. Initially, fully suppressed serum LH and FSH recovered slowly towards the participant's own pre-treatment baseline over 12 months since the last injection. CONCLUSIONS: After stopping 2 years of 1000 mg injectable TU treatment, full reproductive hormone recovery is slow and progressive over 15 months since the last testosterone injection but may take longer than 12 months to be complete. Persistent proportionate reduction in serum SHBG and T reflects lasting exogenous T effects on hepatic SHBG secretion rather than androgen deficiency.

Detection of testosterone microdosing in healthy females.

The ready detectability of synthetic androgens by mass spectrometry (MS)-based antidoping tests has reoriented androgen doping to using testosterone (T), which must be distinguished from its endogenous counterpart making detection of exogenous T harder. We investigated urine and serum steroid and hematological profiling individually and combined to determine the optimal detection model for T administration in women. Twelve healthy females provided six paired blood and urine samples over 2 weeks prior to treatment consisting of 12.5-mg T in a topical transdermal gel applied daily for 7 days. Paired blood and urine samples were then obtained at the end of treatment and Days 1, 2, 4, 7, and 14 days later. Compliance with treatment and sampling was high, and no adverse effects were reported. T treatment significantly increased serum and urine T, serum dihydrotestosterone (DHT), urine 5α-androstane-3α,17ß-diol (5α-diol) epitestosterone (E), and urine T/E ratio with a brief window of detection (2-4 days) as well as total and immature (medium and high fluorescence) reticulocytes that remained elevated over the full 14 posttreatment days. Carbon isotope ratio MS and the OFF score and Abnormal Blood Profile score (ABPS) were not discriminatory. The optimal multivariate model to identify T exposure combined serum T, urine T/E ratio with three hematological variables (% high fluorescence reticulocytes, mean corpuscular hemoglobin, and volume) with the five variables providing 93% correct classification (4% false positive, 10% false negatives). Hence, combining select serum and urine steroid MS variables with reticulocyte measures can achieve a high but imperfect detection of T administration to healthy females.

Optimal injection interval for testosterone undecanoate treatment of hypogonadal and transgender men.

OBJECTIVE: To define the optimized inter-injection interval of injectable testosterone undecanoate (TU) treatment for hypogonadal and transmen based on individual dose titration in routine clinical practice. DESIGN AND METHODS: A prolective observational study of consecutive TU injections in men undergoing testosterone replacement therapy for pathological hypogonadism or masculinization of female-to-male transgender (transmen) subject to individual dosing titration to achieve a stable replacement regimen. RESULTS: From 2006 to 2019, 6899 injections were given to 325 consecutive patients. After excluding the 6-week loading dose, 6300 injections were given to 297 patients who had at least three and a median of 14 injections. The optimal injection interval (mean of last three injection intervals) had a median of 12.0 weeks (interquartile range 10.4-12.7 weeks). The interval was significantly influenced by age and body size (body surface area, BSA) but not by diagnosis or trough serum LH, FSH, and SHBG. Longer (≥14 weeks; 68/297, 23%), but not shorter (≤10 weeks; 22/297, 7.4%), intervals were weakly correlated with age but not diagnosis or other covariables. Low blood hemoglobin increased with trough serum testosterone to reach plateau once testosterone was about 10 nmol/L or higher. CONCLUSION: Optimal intervals between TU injection after individual titration resulted in the approved 12-week interval in 70% of patients with only minor influence for clinical application of BSA and not of trough serum LH, FSH, and SHBG. Individually optimized inter-injection interval did not differ between men with primary or secondary hypogonadism or transmen.

Simplified Method to Measure Mouse Fertility.

Estimating breeding performance from mouse mating trials has focused on lifetime mating trials, which are too slow and costly for characterizing the many novel genetic mouse lines produced in fertility research, an underpinning of reproductive pathophysiology research. This study introduces the fertility index, defined as the slope of the regression of cumulative number of pups produced by a female over elapsed time in a monogamous mating trial. By using a robust resampling technique, the Theil-Sen estimator (widely available in free or niche statistical software), to estimate the fertility index, the present study of 410 mating trials of mice from 7 genotypes lasting a median of 10 litters shows that it is possible to estimate the fertility index reliably over as few as 4 litters.

Pharmacokinetics and Acceptability of Subcutaneous Injection of Testosterone Undecanoate.

CONTEXT: Can injectable testosterone undecanoate (TU) be administered effectively and acceptably by the subcutaneous (SC) route? OBJECTIVE: To investigate the acceptability and pharmacokinetics (PK) of SC injection of TU. DESIGN: Randomized sequence, crossover clinical study of SC vs IM TU injections. SETTING: Ambulatory clinic of an academic andrology center. PARTICIPANTS: Twenty men (11 hypogonadal, 9 transgender men) who were long-term users of TU. injections. Intervention: Injection of 1000 mg TU (in 4 mL castor oil vehicle) by SC or IM route. Main Outcome Measures: Patient-reported pain, acceptability, and preference scales. PK by measurement of serum testosterone, dihydrotestosterone (DHT), and estradiol (E2) concentrations with application of population PK methods and dried blood spot (DBS) sampling. RESULTS: Pain was greater after SC compared with IM injection 24 hours (but not immediately) after injection but both routes were equally acceptable. Ultimately 11 preferred IM, 6 preferred SC, and 3 had no preference. The DBS-based PK analysis of serum testosterone revealed a later time of peak testosterone concentration after SC vs IM injection (8.0 vs 3.3 days) but no significant route differences in model-predicted peak testosterone concentration (8.4 vs 9.6 ng/mL) or mean resident time (183 vs 110 days). The PK of venous serum testosterone, DHT, and E2 did not differ according to route of injection. CONCLUSIONS: We conclude that SC TU injection is acceptable but produces greater pain 24 hours after injection that may contribute to the overall majority preference for the IM injection. The PK of testosterone, DHT, or E2 did not differ substantially between SC and IM routes. Hence whereas further studies are required, the SC route represents an alternative to IM injections without a need to change dose for men for whom IM injection is not desired or recommended.

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

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

Sperm cryopreservation prior to gonadotoxic treatment: experience of a single academic centre over 4 decades.

STUDY QUESTION: What is the natural history of outcomes of sperm cryostorage at an Australian tertiary academic centre? SUMMARY ANSWER: Cryostorage is feasible in virtually all men facing gonadotoxic therapy but the timing of sperm disposal varies according to the reason for it. WHAT IS KNOWN ALREADY: Gonadotoxic treatment for cancer or non-cancer diseases damages spermatogenesis and impairs male fertility. Sperm cryopreservation is an established technique to preserve male fertility prior to gonadotoxic treatment. STUDY DESIGN, SIZE, DURATION: A retrospective review of clinical, anthropometric, semen analysis and hormonal data from 1978 to 2017 involving 2717 men comprising 2085 men with cancer, 234 non-cancer disease and 398 healthy controls, in a single tertiary academic centre with the same clinic and laboratory staff. PARTICIPANTS/MATERIALS, SETTING AND METHODS: Sperm output was analysed according to diseases, the feasibility of sperm cryostorage notably for adolescents, regional access to an urban cryostorage facility, the determinants of sperm output and time-dependent disposal of cryostored sperm. Semen samples were assessed by contemporaneous WHO methods. MAIN RESULTS AND THE ROLE OF CHANCE: Of 2085 men with cancer, 904 (43%) had haematological malignancies, 680 (33%) testicular cancers and 136 (6.5%) were adolescents. Most men (89%) and adolescents (80%) could collect sperm. Sperm output for all cancers and non-cancer diseases was lower than controls. Sperm output correlated positively with total testicular volume (r = 0.44, P < 0.0001) and negatively with serum FSH and LH (r = -0.24, -0.12, respectively, both P < 0.0001) but not testosterone. For all stored samples, the median time in cryostorage was 8.5 years, 7% were transferred for use to induce pregnancy (median time 2.5 years) and 62.2% were discarded as no longer needed (return of fertility, 35.9% median 3.5 years; death, 26.3%, median 6.5 years), the high disposal rate reflecting regular annual follow-up to establish ongoing need for continued cryostorage. Cryostorage facilities are not available in remote and rural areas of the State and the proportion of outer regional and remote area residents cryostoring sperm was only about half that compared with urban residents. LIMITATIONS, REASONS FOR CAUTION: This study does not report the pregnancy outcomes of the patients who used the cryostored sperm, due to recent limitations on health data privacy. WIDER IMPLICATIONS OF THE FINDINGS: Sperm cryostorage is feasible for virtually all men, including sufficiently mature adolescents, who can collect semen to insure future paternity as well as making positive psychological preparation for the patient's survival. Disposal of cryostored material when no longer required is efficient with regular follow-up. Sperm cryopreservation should be an integral part of comprehensive treatment plan in men receiving gonadotoxic treatment but remains underutilized. STUDY FUNDING/COMPETING INTEREST(S): There was no external funding for this study and there were no relevant conflicts of interest.

Estimating age-specific trends in circulating testosterone and sex hormone-binding globulin in males and females across the lifespan.

BACKGROUND: Age-specific trends of serum testosterone and sex hormone-binding globulin across the full lifespan have not been reported. METHODS: We deduced age-specific trends in serum testosterone and sex hormone-binding globulin in males and females between ages 10 and 90 from a large sample of consecutive results from a single large pathology laboratory. Coded results of 110,712 consecutive blood samples requesting serum testosterone over seven years (2007-2013) comprising blood testosterone, sex hormone-binding globulin and calculated free testosterone together with gender and age were analysed create smoothed age-specific centiles (2.5%, 5%, 25%, 50%, 75%, 95%, 97.5%) for males and females. RESULTS: These identified the pubertal increases in serum testosterone in males peaking at 20 years of age and remaining stable thereafter until the eighth decade. In females, circulating testosterone peaked in late adolescence and declined gradually over the next two decades but remained stable across menopause and beyond. After early childhood, serum sex hormone-binding globulin declines to a nadir in males at the age of 20 years and remains stable till the sixth decade with a gradual, progressive rise thereafter. In females, the sex hormone-binding globulin nadir is reached earlier with levels rising gradually and progressively with age thereafter and accelerating after the age of 70 years. Females also exhibit a second sex hormone-binding globulin peak during reproductive ages reflected only in upper centiles due to effects of pregnancy and oral contraceptive use in a significant minority of females. CONCLUSIONS: This large sample of clinical data provides a comprehensive profile of androgen status across the lifespan from early adolescence to late old age.

Age-specific population centiles for androgen status in men.

AIM: The age-specific population profiles in men of circulating testosterone and its two bioactive metabolites dihydrotestosterone (DHT) and estradiol (E2) across the adult lifespan and its determinants are not well described. OBJECTIVE: Our objective was to deduce smoothed age-specific centiles of circulating testosterone, DHT, and E2 in men using pooled data from population-based studies in three Australian cities from liquid chromatography-mass spectrometry steroid measurements in a single laboratory. DESIGN, SETTING, AND PARTICIPANTS: We pooled data of 10 904 serum samples (serum testosterone, DHT, E2, age, height, and weight) from observational population-based studies in three major cities across Australia. MAIN OUTCOME MEASURES: Age-specific smoothed centiles for serum testosterone, DHT, and E2 in men aged 35-100 years were deduced by large sample data analysis methods. RESULTS: We found that serum testosterone, DHT, and E2 decline gradually from ages 35 onwards with a more marked decline after 80 years of age. Higher weight, BMI, and body surface area as well as shorter stature are associated with reduced serum testosterone, DHT, and E2. CONCLUSIONS: Among Australian men, there is a gradual progressive population-wide decline in androgen status during male aging until the age of 80 years after which there is a more marked decline. Obesity and short stature are associated with reduced androgen status. Research into the age-related decline in androgen status should focus on the progressive accumulation of age-related comorbidities to better inform optimal clinical trial design.

Male sexual function can be maintained without aromatization: randomized placebo-controlled trial of dihydrotestosterone (DHT) in healthy, older men for 24 months.

INTRODUCTION: Male sexual function is highly androgen dependent but whether aromatization of testosterone (T) to estradiol is required remains contentious. AIM: This study aims to investigate the effects of selective estrogen deficiency induced by a nonaromatizable androgen, dihydrotestosterone (DHT), on sexual function of healthy middle-aged and older men. METHODS: Randomized clinical trial of daily transdermal DHT (70 mg) or placebo gel treatment in 114 healthy middle-aged and older (>50 years, mean 60.5 years) men without known prostate disease maintaining selective estrogen deficiency for 24 months. OUTCOME MEASURES AND ANALYSIS: The end points were responses to a psychosexual and mood questionnaire completed before, at 3 months, then at 6 monthly intervals during and 3 months after study. Data were analyzed by mixed model analysis of variance for repeated measures using age and body mass index (BMI) as covariates and including interactions of treatment with age and time-on-study. RESULTS: DHT treatment increased serum DHT with complete suppression of serum T, luteinizing hormone, follicle stimulating hormone, and estradiol throughout the 24-month study resulting in reduced spinal bone density. There were no spontaneous complaints, or discontinuations for, adverse effects on sexual function during the study. DHT administration had no effects on any of 33 measures of sexual function and mood, apart from a mild, but significant decrease in overall sexual desire, which was reversible after cessation of treatment. Increasing age and less often increasing BMI were associated with significant decreases in most aspects of sexual function. CONCLUSIONS: We conclude that aromatization plays only a minimal role in maintenance of sexual function in healthy eugonadal middle-aged or older men, but age and obesity are significantly associated with decreases in most aspects of self-reported sexual function and satisfaction. The dependence of male sexual function on aromatization may be conditional on age and obesity and can be overcome by a nonaromatizable androgen.

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

OBJECTIVE: To determine serum concentrations, intra-individual variability and impact of age-related co-morbidities on serum testosterone (T), dihydrotestosterone (DHT), estradiol (E(2)) and estrone (E(1)) in older men. DESIGN: Observational, repeated measures study. PARTICIPANTS: Men (n = 325) with 40 years and older self-reporting very good or excellent health. MEASUREMENTS: Standardized history, physical examination and collection of nine blood samples at fixed time intervals were measured over 3 months (three at 20 min intervals on days 1 (fasting) and 2 (non-fasting), one at days 7, 30 and 90). Serum T, DHT, E(2) and E(1) (n = 2900, > 99% of scheduled samples) measured by liquid chromatography-tandem mass spectrometry (LC-MS) were analysed by linear mixed model analysis with fasting, age and obesity as covariables. RESULTS: Mean serum T did not vary with age (P = 0·76) but obesity (-0·35 nM per body mass index (BMI) unit, P < 0·0001) and ex-smoker status (-1·6 nM, P < 0·001) had significant effects. Serum DHT was increased with age (+0·011 nM per year, P = 0·001) but decreased with obesity (-0·05 nM per BMI unit, P < 0·0001). Serum E(2) did not vary with age (P = 0·31) or obesity (P = 0·12). Overnight fasting increased (by 9-16%, all P < 0·001) and reduced variability in morning serum T, DHT, E(2) and E(1). Non-fasting serum T and DHT were stable over time (day, week, month or 3 months; P > 0·28). CONCLUSIONS: Serum T, DHT and E(2) displayed no decrease associated with age among men over 40 years of age who self-report very good or excellent health although obesity and ex-smoking status were associated with decreased serum androgens (T and DHT) but not E(2). These findings support the interpretation that the age-related decline in blood T accompanying non-specific symptoms in older men may be due to accumulating age-related co-morbidities rather than a symptomatic androgen deficiency state.

Accuracy of calculated free testosterone formulae in men.

BACKGROUND: As reference laboratory methods for measuring free testosterone (FT) by equilibrium dialysis (ED) are laborious, costly and nonautomatable, FT levels are often calculated (cFT) rather than measured. However, the predictive accuracy of such estimates in routine use relative to laboratory measurements is not well defined. We provide a large-scale evaluation of the predictive accuracy for different FT formulae compared with laboratory ED measurement and an analysis of clinical factors that may influence accuracy. METHODS: The accuracy of five different cFT formulae (two equilibrium binding, three empirical) based on immunoassays of total testosterone (TT) and SHBG was evaluated by comparing those estimates with FT measurement by ED in 2159 serum samples from men at a single research laboratory over several years. RESULTS: cFT formulae show systematic discrepancies from the two equilibrium-binding formulae. One empirical formula overestimated FT relative to ED measurements, whereas two newer empirical cFT formulae were more concordant. These discrepancies persisted after correction for serum albumin and were not influenced by obesity, ethnicity or gonadal status. CONCLUSIONS: Commonly used cFT formulae significantly overestimate FT relative to laboratory measurement by ED in male serum samples. The accuracy of the formulae is not influenced by correction for serum albumin, obesity, ethnicity or gonadal status. Such inaccuracy relative to the reference method renders some cFT estimates unreliable for evaluating androgen deficiency as recommended by clinical best practice guidelines.

Randomized cross-over clinical trial of injectable vs. implantable depot testosterone for maintenance of testosterone replacement therapy in androgen deficient men.

BACKGROUND: Life-long testosterone replacement therapy (TRT) for younger men with organic androgen deficiency is best provided by depot testosterone (T) products. This study compared directly the two long-acting depot T products, subdermal T implants (TI) and injectable T undecanoate (TU) for maintenance of TRT. DESIGN, SETTING AND PARTICIPANTS: Men with organic androgen deficiency (n = 38) undergoing regular TRT at an academic Andrology centre were recruited for a two period, randomized sequence, cross-over clinical trial without intervening wash-out period of TRT maintenance. OUTCOMES: For both depot T products, their pharmacokinetics and pharmacodynamics were evaluated using a range of androgen sensitive clinical, laboratory and quality of life measures as well as preference for ongoing treatment after experience of both products. RESULTS: The two depot T products had distinct pharmacokinetics and were not bioequivalent. However, there were no consistent clinical differences in a comprehensive range of pharmacodynamic measures reflecting androgen effects on biochemistry and haematology, muscle mass and strength, and quality of life, mood and sexual function. The majority (91%) of participants chose TU over TI at study completion. CONCLUSION: Despite significant pharmacokinetic differences, the two depot T products are clinically interchangeable allowing for choice dependent on patient and physician delivery preference in practice but most patients preferred the injectable over the implantable form.

Predictive accuracy and sources of variability in calculated free testosterone estimates.

BACKGROUND: Serum free testosterone (FT) concentrations are commonly requested, but because reference FT methods are too laborious various calculational algorithms for FT based on total testosterone (TT) and sex hormone-binding globulin (SHBG) are frequently used. This study provides the first large-scale evaluation of the predictive accuracy and sources of variability for different FT formulae compared with direct laboratory measurements. METHODS: Using a large data-set of direct FT measurements by centrifugal ultrafiltration, the predictive accuracy of five different formulas for cFT (four existing plus a new formula) is evaluated in 3975 consecutive blood samples. In a second data-set of 124 samples from a reference panel of healthy eugonadal young men, we estimate the relative influence of the five algorithms and eight different TT and two SHBG assays including all available commercial total TT and SHBG assays together with a gas chromatography/mass spectrometry T reference method. RESULTS: cFT formulae show wide discrepancies with equilibrium-binding algorithms showing systematic overestimation relative to direct FT measurements, whereas two empirical cFT methods were more concordant. Variations between commercially available TT immunoassays have a strong impact on calculation of FT with TT assays contributing 82.2% of overall variance compared with 13.7% for the cFT algorithms and 4.1% for the SHBG assays. CONCLUSIONS: If FT measurements are requested and direct measurement impractical, cFT formulae using TT and SHBG immunoassays provide an approximation to direct FT measurement that is strongly dependent on the TT, cFT formula used and, to a lesser extent, SHBG immunoassays.

Transperineal ultrasound for measurement of prostate volume: validation against transrectal ultrasound.

PURPOSE: We evaluated the transperineal ultrasound method to measure total and central prostate volume compared with the standard transrectal ultrasound. MATERIALS AND METHODS: Healthy men without prostate disease underwent transperineal and transrectal ultrasound at a single session to calculate total and central prostate volume by the ellipsoidal formula from maximal measured dimensions. Reproducibility within and between methods was evaluated by ICC, CV and Bland-Altman plots. RESULTS: In 13 men measured on 3 occasions within 2 weeks transperineal and transrectal ultrasound had high within method (ICC 0.92 and 0.97, and CV 7.2% and 5.1%, respectively) and between method (ICC 0.98 and CV 5.4%) agreement. Agreement for central prostate volume was good but it was lower within method (ICC 0.74 and 0.73, and CV 20.5% and 20.3%, respectively) and between method (ICC 0.85 and CV 19.7%). Transperineal ultrasound bias was -2.7% for total and -8.9% for central prostate volume. Of 287 healthy men the methods highly correlated for total prostate volume in 245 (ICC 0.92, 95% CI 0.90 to 0.94) and for central prostate volume in 217 (ICC 0.87, 95% CI 0.83 to 0.90). Transperineal ultrasound had minimal bias for total prostate volume (-3.7%, mean -1.0 ml, 95% CI -1.7 to -0.2 ml) and no bias for central prostate volume (-3.0%, mean bias 0.10 ml, 95% CI -0.3 to 0.5 ml). Transperineal ultrasound was more acceptable but it had a higher technical failure rate for total and central prostate volume (13.6% vs 1.4% and 23.7% vs 3.5%, respectively). CONCLUSIONS: Transperineal ultrasound provides an accurate, less invasive and more acceptable alternative but with a higher technical failure rate than transrectal ultrasound, especially for central prostate volume. By trading off acceptability for the failure rate transperineal ultrasound may enhance the feasibility of valid studies requiring repeat prostate volume measurement in asymptomatic men.

Growth and development during early manhood as determinants of prostate size in later life.

BACKGROUND: Age and androgens are key determinants of benign prostate hyperplasia, but the mechanisms remain unclear. We examine the relationship between androgens and total, central, and peripheral prostate volume with a focus on early life factors. METHODS: We conducted a cross-sectional observational study of 406 community-dwelling Australian men aged 20-82 yr old without known prostate disease. Prostate zonal (total, central, and peripheral) volumes were measured by planimetric transrectal ultrasound. Participants completed questionnaires, underwent physical examination, and provided blood samples to measure total, free, and bioavailable testosterone, dihydrotestosterone, estradiol, SHBG, LH, FSH, and prostate-specific antigen. RESULTS: Prostate zonal volumes were positively associated with age, prostate-specific antigen, early onset of puberty, current height, body surface area, lean body mass, hip and waist circumference as well as recalled height and weight during puberty and adolescence but not current weight, fat mass, or body mass index. Stepwise multivariate regression modeling indicated that age and height were the only independent predictors of prostate zonal volumes. When adjusted for age and sampling time of day, the negative correlations of age-adjusted prostate zonal volumes with current blood total, free, and bioavailable testosterone and the positive correlation with blood SHBG were no longer significant. CONCLUSIONS: This study suggests that early and long-term androgen exposure may have long-acting effects on mature prostate zonal volumes, whereas relationships with current blood androgens and related hormones levels were mostly a result of confounding by age. Additional studies on the mechanism of androgen effects on late-life prostate diseases should consider lasting effects of early-life androgen exposure.

Adequacy of androgen replacement influences bone density response to testosterone in androgen-deficient men.

OBJECTIVE: Androgen deficiency (AD) leads to bone loss and contributes to osteoporotic fractures in men. Although low bone mineral density (BMD) in AD men is improved by testosterone replacement, the responses vary between individuals but the determinants of this variability are not well defined. DESIGN AND METHODS: Retrospective review of dual energy X-ray absorptiometry (DEXA) of the lumbar spine and proximal femur in men with established AD requiring regular androgen replacement therapy (ART). After a DEXA scan all men were treated with testosterone implants (800 mg, approximately 6 month intervals). Patients were classified as having a congenital, childhood, or post-pubertal onset, as well as according to the adequacy of treatment prior to their first DEXA scan as untreated, partially treated or well treated. RESULTS: Men with AD requiring regular ART (n = 169, aged 46.3+/-1.1 years, range 22-84 years) underwent a DEXA scan prior to being treated with testosterone implants (800 mg, approximately 6 month intervals). In cross-sectional analysis at the time of the first DEXA scan untreated men (n = 24) had significantly reduced age-adjusted BMD at all four sites (L1-L4, femoral neck, Ward's triangle and trochanter). Well-treated men (n = 77) had significantly better age-adjusted BMD at all four sites compared with those who were partially treated (n = 66) or untreated (n = 24) with their age-adjusted BMD being normalized. In a longitudinal assessment of men (n = 60) who had two or more serial DEXA scans, at the second DEXA scan after a median of 3 years, men who were previously partially treated (n = 19) or untreated (n = 11) had proportionately greater improvements in BMD, significantly for Ward's triangle (P = 0.025) and the trochanter (P = 0.044) compared with men (n = 30) previously well treated. CONCLUSIONS: The present study demonstrates a positive relationship between adequacy of testosterone replacement and BMD in men with overt organic AD. Additionally, the BMD of well-treated AD men approximates that of age-matched non-AD controls. The greatest BMD gains are made by those who have been either untreated or partially treated, and optimal treatment over time (median 3 years) normalizes BMD to the level expected for healthy men of the same age.

Rates of suppression and recovery of human sperm output in testosterone-based hormonal contraceptive regimens.

BACKGROUND: Practical hormonal male contraceptive regimens are likely to have delayed onset and offset of reliable contraception dictated by the length of the spermatogenic cycle and clearance rate of pre-formed sperm from the ductular system. While delayed onset of contraceptive efficacy is an accepted feature of vasectomy, reliable time estimates for a hormonal male contraceptive of time to onset and offset of reliable contraception and of resumption of normal male fertility are required. METHODS AND RESULTS: We utilized the sperm output data from three male contraceptive efficacy studies to define quantitative estimates of suppression and recovery rates from an androgen alone (testosterone enanthate) and an androgen/progestin (testosterone/depot medroxyprogesterone acetate) study. Using nearly 14,000 semen samples from World Health Organization (WHO) studies #85921 and #89903 with identical protocols, the rate of suppression of sperm output was best modelled as a two-parameter, single exponential decay function with effective half-time to suppression of 5.5 weeks and times of 6.8 weeks to 10 x 10(6)/ml, 8.7 weeks to 5 x 10(6)/ml, 10.0 weeks to 3 x 10(6)/ml and 13.0 weeks to 1 x 10(6)/ml. The rate of recovery using absolute sperm concentration was best modelled as a three-parameter, sigmoidal curve with effective time to reach half of the recovery plateau of 10.5 weeks and times of 9.0 weeks to 3 x 10(6)/ml, 9.9 weeks to 5 x 10(6)/ml, 11.5 weeks to 10 x 10(6)/ml, and 13.6 weeks to 20 x 10(6)/ml. Using relative sperm output, defined as a percentage of the participants' own baseline, recovery approached an asymptotic plateau of approximately 85% of geometric mean pre-treatment sperm concentration. In the combination androgen/progestin study, suppression rate was significantly faster (effective time to reach half maximal suppression of 3.0 weeks) and recovery significantly slower (effective time to reach half of recovery plateau of 14.7 weeks) and less complete (asymptotic recovery plateau of 43% of baseline) than in the androgen-alone WHO studies. CONCLUSION: These findings therefore provide large sample estimates of the suppression and recovery rates from an androgen-alone hormonal male contraceptive regimen as a basis for comparison with other second-generation combination androgen/progestin regimens that are the most promising approach to developing practical male hormonal regimens.

Empirical estimation of free testosterone from testosterone and sex hormone-binding globulin immunoassays.

BACKGROUND: The growing interest in measuring blood free testosterone (FT) is constrained by the unsuitability of the laborious reference methods for wider adoption in routine diagnostic laboratories. Various alternative derived testosterone measures have been proposed to estimate FT from either additional assay steps or calculations using total testosterone (TT) and sex hormone-binding globulin (SHBG) measured in the same sample. However, none have been critically validated in large numbers of blood samples. METHODS: We analyzed a large dataset comprising over 4000 consecutive blood samples in which FT as well as TT and SHBG were measured. Dividing the dataset into samples with blood TT above and below 5 nM, using a bootstrap regression modeling approach guided by Akaike Information Criterion for model selection to balance parsimony against reduction of residual error, empirical equations were developed for FT in terms of TT and SHBG. RESULTS: Comparison between the empirical FT equations with the laboratory FT measurements as well as three widely used calculated FT methods showed the empirical FT formulae had superior fidelity with laboratory measurements while previous FT formulae overestimated and deviated systematically from the laboratory FT values. CONCLUSION: We conclude that these simple, assumption-free empirical FT equations can estimate accurately blood FT from TT and SHBG measured in the same samples with the present assay methods and have suitable properties for wider application to evaluate the clinical utility of blood FT measurements.