10th Summit Meeting consensus: recommendations for regulatory approval for hormonal male contraception.
Explore the source record for details and available documents.
Contraceptive Agents, Male↗
Biomedical subjects
William J Bremner
Publications and source records attributed to William J Bremner.
Testosterone gel combined with depomedroxyprogesterone acetate is an effective male hormonal contraceptive regimen and is not enhanced by the addition of a GnRH antagonist.
INTRODUCTION: Exogenous androgens plus progestins can be used to suppress spermatogenesis, resulting in effective male hormonal contraception; however, induction of azoospermia can require 3-6 months, and these methods require injectable or implantable androgens. We hypothesized that testosterone (T) transdermal gel (T gel) could be combined with a depot formulation of the progestin, depomedroxyprogesterone acetate (DMPA), with or without the potent GnRH antagonist, acyline, to suppress spermatogenesis conveniently, rapidly, and reversibly. OBJECTIVES: The objectives of the study were: 1) to determine the rate of severe oligospermia (< or = 1 million sperm/ml) using T gel+DMPA; and 2) to determine whether the addition of acyline to T gel+DMPA during the first 12 wk of the regimen would accelerate and improve suppression of spermatogenesis. METHODS: Forty-four healthy men, ages 18-55 yr, were randomized to T gel (100 mg daily)+DMPA (300 mg/3 months) or acyline (300 microg/kg.2 wk x 12 wk)+T gel+DMPA. Thirty-eight men completed the 24-wk treatment protocol. RESULTS: All men had dramatic suppression of spermatogenesis; 90% of the subjects became severely oligospermic, a rate comparable to implantable and injectable T+progestin combinations. The addition of acyline did not significantly accelerate spermatogenic suppression or improve rates of severe oligospermia. There were no serious adverse events, and there were minimal changes in weight, serum lipids, and prostate-specific antigen. CONCLUSIONS: The combination of T gel+DMPA is a promising new regimen in male contraception. The addition of the GnRH antagonist acyline, as part of an induction phase in a male contraception regimen, has limited clinical utility. Additional studies using T gel for male contraception are warranted.
Administration, Topical↗
Persistent intraprostatic androgen concentrations after medical castration in healthy men.
CONTEXT: The impact of serum androgen manipulation on prostate tissue hormone levels in normal men is unknown. Studies of men with prostate cancer have suggested that prostatic androgens are preserved in the setting of castration. Tissue androgens might stimulate prostate growth, producing adverse clinical consequences. OBJECTIVE: The objective of the study was to determine the effect of serum androgen manipulation on intraprostatic androgens in normal men. DESIGN: Thirteen male volunteers ages 35-55 yr (prostate-specific antigen < 2.0 ng/ml; normal transrectal ultrasound) were randomly assigned to: 1) a long-acting GnRH-antagonist, acyline, every 2 wk; 2) acyline plus testosterone (T) gel (10 mg/d); or 3) placebo for 28 d. Serum hormones were assessed weekly. Prostate biopsies were obtained on d 28. Extracted androgens were measured by RIA, and immunohistochemistry for androgen-regulated proteins was performed. RESULTS: The mean decrease in serum T was 94%, whereas prostatic T and dihydrotestosterone levels were 70 and 80% lower, respectively, in subjects receiving acyline alone compared with controls (P < 0.05). Despite this decrease in prostate androgens, there were no detectable differences in prostate epithelial proliferation, apoptosis, prostate-specific antigen, and androgen receptor expression. CONCLUSION: In this small study of healthy subjects, despite a 94% decrease in serum T with medical castration, intraprostatic T and dihydrotestosterone levels remained 20-30% of control values, and prostate cell proliferation, apoptosis, and androgen-regulated protein expression were unaffected. Our data highlight the importance of assessing tissue hormone levels. The source of persistent prostate androgens associated with medical castration and their potential role in supporting prostate metabolism deserves further study.
Adult↗
Low sex hormone-binding globulin, total testosterone, and symptomatic androgen deficiency are associated with development of the metabolic syndrome in nonobese men.
BACKGROUND: The metabolic syndrome (MetS), characterized by central obesity, lipid and insulin dysregulation, and hypertension, is a precursor state for cardiovascular disease. The purpose of this analysis was to determine whether low serum sex hormone levels or clinical androgen deficiency (AD) predict the development of MetS. METHODS: Data were obtained from the Massachusetts Male Aging Study, a population-based prospective cohort of 1709 men observed at three time points (T1, 1987-1989; T2, 1995-1997; T3, 2002-2004). MetS was defined using a modification of the ATP III guidelines. Clinical AD was defined using a combination of testosterone levels and clinical signs and symptoms. The association between MetS and sex hormone levels or clinical AD was assessed using relative risks (RR), and 95% confidence intervals (95% CI) were estimated using Poisson regression models. RESULTS: Analysis was conducted in 950 men without MetS at T1. Lower levels of total testosterone and SHBG were predictive of MetS, particularly among men with a body mass index (BMI) below 25 kg/m2 with adjusted RRs for a decrease in 1 sd of 1.41 (95% CI, 1.06-1.87) and 1.65 (95% CI, 1.12-2.42). Results were similar for the AD and MetS association, with RRs of 2.51 (95% CI, 1.12-5.65) among men with a BMI less than 25 compared with an RR of 1.22 (95% CI, 0.66-2.24) in men with a BMI of 25 or greater. CONCLUSIONS: Low serum SHBG, low total testosterone, and clinical AD are associated with increased risk of developing MetS over time, particularly in nonoverweight, middle-aged men (BMI, <25). Together, these results suggest that low SHBG and/or AD may provide early warning signs for cardiovascular risk and an opportunity for early intervention in nonobese men.
Adult↗
Drug insight: Recent advances in male hormonal contraception.
As there are limitations to current methods of male contraception, research has been undertaken to develop hormonal contraceptives for men, analogous to the methods for women based on estrogen and progestogens. When testosterone is administered to a man, it functions as a contraceptive by suppressing the secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary gland. Since these hormones are the main stimulatory signals for spermatogenesis, low levels of LH and FSH markedly impair sperm production. After 3-4 months of testosterone treatment, 60-70% of men no longer have sperm in their ejaculate, and most other men exhibit markedly diminished sperm counts. Male hormonal contraception is well tolerated, free of serious adverse side effects, and 95% effective in the prevention of pregnancy. Importantly, male hormonal contraception is reversible, with sperm counts usually recovering within 4 months of the discontinuation of hormone treatment. Because exogenous testosterone administration alone does not completely suppress sperm production in all men, researchers have combined testosterone with second agents, such as progestogens or gonadotropin-releasing-hormone antagonists, to further suppress secretion of LH and FSH and improve suppression of spermatogenesis. Recent trials have used combinations of long-acting injectable or implantable forms of testosterone with progestogens, which can be administered orally, by injection or by a long-acting implant. Such combinations suppress spermatogenesis to zero without severe side effects in 80-90% of men, with near-complete suppression in the remainder of individuals. One of these testosterone and progestogen combination regimens might soon bring the promise of male hormonal contraception to fruition.
Administration, Cutaneous↗
Transdermal androgen therapy to augment EPO in the treatment of anemia of chronic renal disease.
BACKGROUND: Hypogonadism and anemia are common comorbid conditions in dialysis patients. Testosterone replacement may improve such clinical parameters as anemia, sarcopenia, and low libido. Additionally, by increasing hemoglobin levels, testosterone replacement may allow for a dose reduction in recombinant human erythropoietin (rHuEPO), thereby reducing cost. METHODS: This phase IV, single-center, placebo-controlled, double-blind study assessed the effect of transdermal testosterone on serum testosterone levels, rHuEPO dose required to maintain hemoglobin level, bone mineral content, lean body mass and fat content, cholesterol level, sexual function, and mood. Forty hypogonadal male hemodialysis patients who were administered rHuEPO were randomly assigned to 100 mg of topical 1% testosterone gel (Testim; Auxilium Pharmaceuticals, Norristown, PA) or placebo, applied daily for 6 months. RESULTS: Forty men with a mean age of 56 years and baseline serum testosterone level less than 300 ng/dL (< 10.4 nmol/L) participated in this trial. In men assigned to administration of transdermal testosterone, there was an increase beyond that in the placebo group in mean serum testosterone (77.1 ng/dL [2.7 nmol/L]), dihydrotestosterone (DHT; 0.8 nmol/L), and estradiol levels (6.3 pg/mL [23.0 pmol/L]) and a decrease in mean serum luteinizing hormone levels (-3.1 IU/L). Compared with subjects administered placebo, participants on testosterone replacement therapy did not show an appreciable change in rHuEPO dose (mean difference adjusted for baseline values, 12.6 U/kg/wk; P = 0.73), bone mineral density, lean body mass or fat content, cholesterol level, sexual function, or mood. CONCLUSION: Daily administration of 100 mg of topical 1% testosterone gel for 6 months failed to significantly increase serum testosterone or DHT levels in hypogonadal men with end-stage renal disease. Treatment with transdermal testosterone did not impact on rHuEPO requirement or clinical parameters in this small placebo-controlled study. Greater serum testosterone levels may be required to show clinical benefit in men with end-stage renal disease.
Administration, Cutaneous↗
The androgen receptor gene CAG repeat polymorphism does not predict increased risk of heart disease: longitudinal results from the Massachusetts Male Ageing Study.
OBJECTIVE: Sex steroids may contribute to the increased prevalence of heart disease (HD) in men compared to age-matched women. Androgens bind their cognate receptor, and androgen action is inversely proportional to the number of CAG repeats in exon 1 of the androgen receptor gene. Longer, less androgenic CAG repeats have been associated with higher high-density lipoprotein (HDL) levels, which might protect against HD. Therefore, we hypothesized that CAG repeat length contributes to HD risk in men. DESIGN: Longitudinal, population-based cohort study. POPULATION: One thousand thirty-four participants from the Massachusetts Male Ageing Study, a cohort of 1709 men from the Boston area, aged 40-70, observed at three time points over 15 years. METHODS: Poisson regression. MEASUREMENTS: Heart disease was determined by self-report, medical records or from the National Death Index. Lipids and hormones were measured from blood samples drawn at each time point. CAG repeat length was assessed from DNA collected at the second time point. RESULTS: We found no increased risk of HD associated with CAG repeat length in our analyses. Moreover, CAG repeat length was not related to body mass index, HDL, low-density lipoprotein or waist to hip ratio in this cohort; nor did CAG repeat length predict changes in these variables over 15 years of follow-up. CONCLUSIONS: In contrast to previous smaller, cross-sectional analyses, in this large cohort of community-dwelling men followed over 15 years, CAG repeat length was not related to the incidence or prevalence of HD or alterations in HDL. If androgens impact HD risk, this effect is unlikely to be mediated via CAG repeat length.
Aging↗
Effect of medical castration on CD4+ CD25+ T cells, CD8+ T cell IFN-gamma expression, and NK cells: a physiological role for testosterone and/or its metabolites.
The higher prevalence of autoimmune disease among women compared with men suggests that steroids impact immune regulation. To investigate how sex steroids modulate cellular immune function, we conducted a randomized trial in 12 healthy men aged 35-55 yr treated for 28 days with placebo, a GnRH antagonist, acyline to induce medical castration, or acyline plus daily testosterone (T) gel to replace serum T, followed by a 28-day recovery period. Serum hormones were measured weekly and peripheral blood lymphocytes (PBLs) were collected biweekly for analyses of thymus-derived lymphocyte (T cell) subtypes and natural killer (NK) cells. Compared with the other groups and to baseline throughout the drug exposure period, men receiving acyline alone had significant reductions in serum T (near or below castrate levels), dihydrotestosterone, and estradiol (P < 0.05). Medical castration significantly reduced the percentage of CD4+ CD25+ T cells (P < 0.05), decreased mitogen-induced CD8+ T cell IFN-gamma expression, and increased the percentage of NK cells without affecting the ratio of CD4+ to CD8+ T cells and the expression of NK cell-activating receptor NKG2D or homing receptor CXCR1. No changes in immune composition were observed in subjects receiving placebo or acyline with replacement T. These data suggest that T and/or its metabolites may help maintain the physiological balance of autoimmunity and protective immunity by preserving the number of regulatory T cells and the activation of CD8+ T cells. In addition, sex steroids suppress NK cell proliferation. This study supports a complex physiological role for T and/or its metabolites in immune regulation.
Adult↗
Effects of testosterone and levonorgestrel combined with a 5alpha-reductase inhibitor or gonadotropin-releasing hormone antagonist on spermatogenesis and intratesticular steroid levels in normal men.
CONTEXT: Combination of a GnRH antagonist (acyline), types I and II, 5alpha-reductase inhibitor (dutasteride) or levonorgestrel (LNG) with testosterone (T) treatment may augment the suppression of spermatogenesis and intratesticular (iT) steroids. OBJECTIVE: The objective of this study was to assess the effects of combined hormonal contraceptive regimens on germ cell populations and iT steroids. DESIGN, SETTING, AND PARTICIPANTS: Twenty-nine normal health men enrolled in this prospective, randomized, 14-wk study at the University of Washington. INTERVENTION(S): Twenty-two men (n = 5-6/group) received 8 wk of T enanthate (TE; 100 mg, i.m., weekly) combined with 1) 125 microg LNG daily, orally; 2) 125 microg LNG plus 0.5 mg dutasteride daily, orally; 3) 300 microg/kg acyline twice weekly, s.c.; or 4) 125 microg LNG daily, orally, plus 300 microg/kg acyline twice weekly, s.c. Subjects then underwent a vasectomy and testicular biopsy. Control men (n = 7) proceeded directly to surgery. MAIN OUTCOME MEASURE(S): The main outcome measures were germ cells and iT steroids [T, dihydrotestosterone, 3alpha- and beta-androstanediol (Adiol), and estradiol (E2)]. RESULTS: High iT levels of all androgens (6- to 123-fold serum levels) and E2 (407-fold serum levels) were found in control men. iTT (1.9-2.6% control; P < 0.001) and iT3betaAdiol (16-34% control; P < 0.05) levels decreased with all treatments. iT dihydrotestosterone (13-29% control; P < 0.05) and iT3alphaAdiol (44-47% control; P < 0.05) levels decreased with all but the TE plus LNG treatment. iTE2 levels decreased only in the TE plus acyline group (28% control; P = 0.01). Germ cells from type B spermatogonia onward were suppressed, with no differences between groups found. Variable sites of impairment of germ cell progression were evident between men (spermagonial maturation, meiosis 1 entry, and spermiation). Other than a negative correlation between iT3alphaAdiol and haploid germ cell number (P < 0.006), no correlations between germ cell number and gonadotropins, sperm concentration, or iT steroids were found. CONCLUSIONS: A similar high testicular:serum gradient exists for E2 and T in normal men, and 8 wk of gonadotropin suppression markedly reduces iTT, with 5alpha-reduced androgens and E2 levels decreasing to a much lesser degree. The heterogeneity of the germ cell response, regardless of treatment, gonadotropins or iT steroids, points to the individual sensitivity of sites in germ cell development, which is worthy of additional exploration.
5-alpha Reductase Inhibitors↗
Low-dose human chorionic gonadotropin maintains intratesticular testosterone in normal men with testosterone-induced gonadotropin suppression.
In previous studies of testicular biopsy tissue from healthy men, intratesticular testosterone (ITT) has been shown to be much higher than serum testosterone (T), suggesting that high ITT is needed relative to serum T for normal spermatogenesis in men. However, the quantitative relationship between ITT and spermatogenesis is not known. To begin to address this issue experimentally, we determined the dose-response relationship between human chorionic gonadotropin (hCG) and ITT to ascertain the minimum dose needed to maintain ITT in the normal range. Twenty-nine men with normal reproductive physiology were randomized to receive 200 mg T enanthate weekly in combination with either saline placebo or 125, 250, or 500 IU hCG every other day for 3 wk. ITT was assessed in testicular fluid obtained by percutaneous fine needle aspiration at baseline and at the end of treatment. Baseline serum T (14.1 nmol/liter) was 1.2% of ITT (1174 nmol/liter). LH and FSH were profoundly suppressed to 5% and 3% of baseline, respectively, and ITT was suppressed by 94% (1234 to 72 nmol/liter) in the T enanthate/placebo group. ITT increased linearly with increasing hCG dose (P < 0.001). Posttreatment ITT was 25% less than baseline in the 125 IU hCG group, 7% less than baseline in the 250 IU hCG group, and 26% greater than baseline in the 500 IU hCG group. These results demonstrate that relatively low dose hCG maintains ITT within the normal range in healthy men with gonadotropin suppression. Extensions of this study will allow determination of the ITT concentration threshold required to maintain spermatogenesis in man.
Adolescent↗
Oral testosterone in oil plus dutasteride in men: a pharmacokinetic study.
Testosterone (T) is not administered orally, because it has been reported to be rapidly metabolized by the liver. We hypothesized that sufficient doses of T or T enanthate (TE), administered orally in oil, would result in clinically useful elevations in serum T. We also hypothesized that coadministration of dutasteride (D) with T or TE would minimize increases in serum DHT seen previously with oral administration. Therefore, we conducted a pharmacokinetic study of oral T and TE in oil, with and without concomitant D, in normal men whose T production had been temporarily suppressed by the GnRH antagonist acyline. Thirteen healthy men (mean age, 24 +/- 6 yr) were enrolled and assigned to oral T (n = 7) and oral TE (n = 6) groups and were administered 200, 400, or 800 mg of either T or TE in sesame oil in the morning on 3 successive days 24 h after receiving acyline. Blood samples for measurement of serum T and dihydrotestosterone were obtained before T or TE administration and 0.5, 1, 2, 4, 6, 8, 10, 12, and 24 h after administration. Subjects were then administered D for 4 d before repeating the sequence of T or TE doses with D. Serum T was significantly increased in a dose-dependent fashion with the administration of oral T or TE in oil. Coadministration of D with oral T or TE significantly increased the 24-hr average serum T levels compared with administration of T or TE alone [average serum T after 400 mg dose, 8.7 +/- 3.0 nmol/l (T) and 8.3 +/- 5.7 nmol/l (TE) vs. 16.1 +/- 5.8 nmol/l (T +D) and 15.0 +/- 8.8 nmol/l (TE + D); P < 0.05 for T vs. T and D]. The administration of oral T or TE in oil combined with D results in unexpected and potentially therapeutic increases in serum T. Additional studies of this combination as a novel form of oral androgen therapy are warranted.
Administration, Oral↗
Exogenous testosterone (T) alone or with finasteride increases physical performance, grip strength, and lean body mass in older men with low serum T.
Testosterone (T) therapy in older men with low serum T levels increases lean body mass and decreases fat mass. These changes might improve physical performance and strength; however, it has not been established whether T therapy improves functional outcome in older men. Moreover, concerns exist about the impact of T therapy on the prostate in older men. The administration of finasteride (F), which partially blocks the conversion of T to the more potent androgen, dihydrotestosterone, attenuates the impact of T replacement on prostate size and prostate-specific antigen. We hypothesized that T replacement in older, hypogonadal men would improve physical function and that the addition of F to this regimen would continue to provide the T-induced improvements in physical performance, strength, and body composition. Seventy men with low serum T (<350 ng/dl), age 65 yr and older, were randomly assigned to receive one of three regimens for 36 months: 1) T enanthate, 200 mg im every 2 wk, with placebo pills daily (T-only); 2) T enanthate, 200 mg every 2 wk, with 5 mg F daily (T + F); or 3) placebo injections and pills (placebo). We obtained serial measurements of timed physical performance, grip strength, lower extremity strength, body composition (by dual-energy x-ray absorptiometry), fasting cholesterol profiles, and hormones. Fifty men completed the 36-month protocol. After 36 months, T therapy significantly improved performance in a timed functional test when compared with baseline and placebo [4.3 +/- 1.6% (mean +/- sem, T-only) and 3.8 +/- 1.0% (T + F) vs. -5.6 +/- 1.9% for placebo (P < 0.002 for both T and T + F vs. placebo)] and increased handgrip strength compared with baseline and placebo (P < 0.05). T therapy increased lean body mass [3.77 +/- 0.55 kg (T-only) and 3.64 +/- 0.56 kg (T + F) vs. -0.21 +/- 0.55 kg for placebo (P < 0.0001)], decreased fat mass, and significantly decreased total cholesterol, low-density lipoprotein, and leptin, without affecting high-density lipoprotein, adiponectin, or fasting insulin levels. These results demonstrate that T therapy in older men with low serum T improves physical performance and strength over 36 months, when administered alone or when combined with F, and suggest that high serum levels of dihydrotestosterone are not essential for these beneficial effects of T in men.
Adiponectin↗
Reproductive ageing and ovarian function: is the early follicular phase FSH rise necessary to maintain adequate secretory function in older ovulatory women?
BACKGROUND: Serum FSH elevations and decreases in inhibin B have been consistently demonstrated in the early follicular phase of cycles in women of advanced reproductive age. However, secretory products of the dominant follicle (estradiol and inhibin A) in the serum of older ovulatory women are maintained at levels similar to those of their younger counterparts. The goal of this investigation was to determine if ovarian secretory capacity is dependent on relative FSH levels and if basal measures of ovarian reserve reflect ovarian secretory capacity. METHODS: We administered equivalent low, but effective doses of recombinant FSH for 5 days to a group of older subjects (40-45 years, n=9) and younger controls (20-25 years, n=10) after pituitary suppression with a GnRH agonist. Outcome measures included follicular development as determined by serial transvaginal ultrasound examinations and serum levels of estradiol, inhibin A and inhibin B. RESULTS: Serum levels of estradiol and inhibin A were not statistically different between the two groups, while the number of large follicles formed was greater in the younger subjects. Basal parameters of ovarian reserve were not significantly correlated with ovarian secretory capacity, but did correlate with the number of follicles recruited in response to low-dose FSH. CONCLUSIONS: By providing equivalent serum levels of FSH in older and younger reproductive aged women, this study demonstrates that the secretory capacity of recruited follicles is maintained in older reproductive aged women.
Adult↗
Novel male hormonal contraceptive combinations: the hormonal and spermatogenic effects of testosterone and levonorgestrel combined with a 5alpha-reductase inhibitor or gonadotropin-releasing hormone antagonist.
We postulated that the addition of a combined types I and II, 5alpha-reductase inhibitor (dutasteride) or long-acting GnRH antagonist (acyline) to combination testosterone plus levonorgestrel treatment may be advantageous in the suppression of spermatogenesis for male contraception. This study aimed to examine effects of novel combination contraceptive regimens on serum gonadotropins and androgens and sperm concentration.This study was divided into three phases: screening (2 wk), treatment (8 wk), and recovery (4 wk). Twenty-two men (n = 5-6/group) received 8 wk of treatment with testosterone enanthate (TE, 100 mg im weekly) combined with one of the following: 1) levonorgestrel (LNG) 125 mug orally daily; 2) LNG 125 microg plus dutasteride 0.5 mg orally daily; 3) acyline 300 microg/kg sc every 2 wk (as a comparator for any additional progestin effects); or 4) LNG 125 microg orally daily plus acyline 300 microg/kg sc every 2 wk. Serum gonadotropin levels were similarly suppressed by all treatments, falling to a nadir between 1.2 and 3.4% and 0.5 and 0.8% baseline for FSH and LH, respectively (P < 0.05). Serum dihydrotestosterone levels were significantly (P < 0.05) decreased in the dutasteride group throughout the treatment period to a nadir of 31% baseline (wk 7). No significant differences in sperm concentrations among treatment groups were seen. Severe oligospermia (0.1-3 million/ml) or azoospermia was seen in none of five and four of five in TE + LNG; two of six and four of six in TE + LNG + dutasteride; two of six and four of six in TE + acyline; and one of five and three of five in TE + LNG + acyline groups, respectively. There was one nonresponder in each of the TE + LNG and TE + LNG + acyline groups.We conclude that the addition of a combined types I and II, 5alpha-reductase inhibitor or long-acting GnRH antagonist to a testosterone plus LNG regimen provides no additional suppression of gonadotropins or sperm concentration over an 8-wk treatment period. However, further evaluation of the effects of these regimens on the testis (including testicular steroid levels and germ cell maturation) and the treatment of larger numbers of men (and for longer periods) may provide data to support their place in contraceptive development.
Adult↗
Effects of occupational solvent exposure on reproductive hormone concentrations and fecundability in men.
BACKGROUND: Little is known about the effects of organic solvents on male reproductive health. To assess fertility and reproductive endocrine function in solvent-exposed men, we investigated time-to-pregnancy using a retrospective cohort design and cross-sectionally measured reproductive hormone concentrations in painters and millwrights compared to a reference group of carpenters. METHODS: Detailed occupational, exposure, medical, and time-to-pregnancy histories were obtained by telephone interview. Plasma luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone concentrations were determined by immunoassay. Exposure indices, which summarized working life exposure to total solvents, chlorinated solvents, aromatic solvents, and thinners, degreasers, varnishes, and adhesives as a category were calculated from exposure histories. RESULTS: FSH concentrations increased significantly with increasing exposure indices for all solvents and for chlorinated solvents. There were no significant associations of solvent exposure indices with LH or testosterone levels. LH, FSH, and testosterone concentrations also did not differ by job title. Using Cox regression, time-to-pregnancy was non-significantly longer in the painters and millwrights than the carpenters. There was no significant association between time-to-pregnancy and any of the solvent exposure indices; however, it should be noted that some of the pregnancies occurred more than 20 years previously, potentially reducing the reliability of the retrospectively collected pregnancy and exposure data. CONCLUSIONS: The significant associations between FSH levels and solvent exposure indices suggest the potential for adverse effects of solvent exposures on reproductive function in men.
Adult↗
Relationship between serum gonadotropins and spermatogenic suppression in men undergoing steroidal contraceptive treatment.
This study aimed to establish whether the degree of suppression of serum FSH and LH was related to sperm concentration in three testosterone (T) plus progestin contraceptive regimens. We measured serum FSH and LH using a modified, highly sensitive immunofluorometric assay in samples obtained from three published studies using T enanthate (TE; 100 and 200 mg weekly) plus daily oral doses of cyproterone acetate (CPA; 5-100 mg), levonogestrel (LNG; 150-500 micro g), or desogestrel (DSG; 150-300 micro g). Overall, men with sperm concentrations below 0.1 million/ml had significantly lower gonadotropin levels (serum FSH, approximately 0.12 IU/liter; serum LH, approximately 0.05 IU/liter) than oligospermic men (sperm concentrations, 0.1-5 million/ml; serum FSH, 0.23-0.5 IU/liter; serum LH, 0.05-0.56 IU/liter), but the relationship was weak, indicating the possible existence of other determinants. Multivariate logistic regression was used to identify the influence of candidate predictors of spermatogenic effects of the T plus progestin regimens. In the LNG and DSG studies, the marked suppression of serum LH to less than 5% of baseline values (<0.15 IU/liter) was a consistent and highly significant predictor of sperm concentration (reduced to 2-7% that seen at higher LH levels) and the likelihood of its suppression below 1 million/ml (a proposed threshold for contraceptive efficacy). Serum FSH was not a significant independent predictor. The use of DSG and CPA (but not LNG) was a significant independent predictor of sperm suppression, and regimens that contained 200 mg TE weekly caused less spermatogenic suppression than 100 mg TE weekly. These findings suggest that T-progestin contraceptive regimens suppress sperm concentration by gonadotropin-dependent and -independent mechanisms. The suppression of serum LH is a major predictor of the suppression of sperm concentration suppression in the LNG and DSG treatment studies. On the other hand, the greater spermatogenic suppression in regimens containing DSG or CPA suggests that these progestins have additional actions to suppress spermatogenesis via a gonadotropin-independent mechanism(s)
Contraceptive Agents, Male↗
Exogenous testosterone or testosterone with finasteride increases bone mineral density in older men with low serum testosterone.
Older men, particularly those with low serum testosterone (T) levels, might benefit from T therapy to improve bone mineral density (BMD) and reduce fracture risk. Concerns exist, however, about the impact of T therapy on the prostate in older men. We hypothesized that the combination of T and finasteride (F), a 5 alpha-reductase inhibitor, might increase BMD in older men without adverse effects on the prostate. Seventy men aged 65 yr or older, with a serum T less than 12.1 nmol/liter on two occasions, were randomly assigned to receive one of three regimens for 36 months: T enanthate, 200 mg im every 2 wk with placebo pills daily (T-only); T enanthate, 200 mg every 2 wk with 5 mg F daily (T+F); or placebo injections and pills (placebo). Low BMD was not an inclusion criterion. We obtained serial measurements of BMD of the lumbar spine and hip by dual x-ray absorptiometry. Prostate-specific antigen (PSA) and prostate size were measured at baseline and during treatment to assess the impact of therapy on the prostate. Fifty men completed the 36-month protocol. By an intent-to-treat analysis including all men for as long as they contributed data, T therapy for 36 months increased BMD in these men at the lumbar spine [10.2 +/- 1.4% (mean percentage increase from baseline +/- SEM; T-only) and 9.3 +/- 1.4% (T+F) vs. 1.3 +/- 1.4% for placebo (P < 0.001)] and in the hip [2.7 +/- 0.7% (T-only) and 2.2 +/- 0.7% (T+F) vs. -0.2 +/- 0.7% for placebo, (P < or = 0.02)]. Significant increases in BMD were seen also in the intertrochanteric and trochanteric regions of the hip. After 6 months of therapy, urinary deoxypyridinoline (a bone-resorption marker) decreased significantly compared with baseline in both the T-only and T+F groups (P < 0.001) but was not significantly reduced compared with the placebo group. Over 36 months, PSA increased significantly from baseline in the T-only group (P < 0.001). Prostate volume increased in all groups during the 36-month treatment period, but this increase was significantly less in the T+F group compared with both the T-only and placebo groups (P = 0.02). These results demonstrate that T therapy in older men with low serum T increases vertebral and hip BMD over 36 months, both when administered alone and when combined with F. This finding suggests that dihydrotestosterone is not essential for the beneficial effects of T on BMD in men. In addition, the concomitant administration of F with T appears to attenuate the impact of T therapy on prostate size and PSA and might reduce the chance of benign prostatic hypertrophy or other prostate-related complications in older men on T therapy. These findings have important implications for the prevention and treatment of osteoporosis in older men with low T levels.
Aged↗
Male hormonal contraception: effects of injections of testosterone undecanoate and depot medroxyprogesterone acetate at eight-week intervals in chinese men.
Surveys indicate that one form of acceptable male hormonal contraception would consist of injections given at 2- to 3-month intervals. This report describes a study of depot medroxyprogesterone acetate (DMPA) and testosterone undecanoate (TU) injected at 8-wk intervals for suppression of spermatogenesis in healthy Chinese men. After screening, 30 healthy volunteers were enrolled and randomly assigned to one of three dose groups (n = 10/group): 1000 mg TU (group A); 1000 mg TU plus 150 mg DMPA (group B); 1000 mg TU plus 300 mg DMPA (group C). All doses were given as im injections at 8-wk intervals. The study consisted of an 8-wk control (baseline) period, a 24-wk treatment period, and a 24-wk recovery period. Consistent azoospermia or severe oligozoospermia was achieved and maintained in all volunteers during the treatment period, except for two men in the TU-alone group who experienced a rebound in sperm concentrations. An 8-wk regimen of TU plus DMPA at both tested combination doses effectively suppressed spermatogenesis to azoospermia in Chinese men. All volunteers tolerated the injections; no serious adverse effects were reported. The lower-dose combination is recommended for further testing in an expanded clinical trial or contraceptive efficacy study.
Adult↗