Practice and development of male contraception: European Academy of Andrology and American Society of Andrology guidelines

BACKGROUNDS

Despite a wide spectrum of contraceptive methods for women, the unintended pregnancy rate remains high (45% in the US), with 50% resulting in abortion. Currently, 20% of global contraceptive use is male-directed, with a wide variation among countries due to limited availability and lack of efficacy. Worldwide studies indicate that >50% of men would opt to use a reversible method, and 90% of women would rely on their partner to use a contraceptive. Additional reasons for novel male contraceptive methods to be available include the increased life expectancy, sharing the reproductive risks among partners, social issues, the lack of pharma industry involvement and the lack of opinion makers advocating for male contraception.

AIM

The present guidelines aim to review the status regarding male contraception, the current state of the art to support the clinical practice, recommend minimal requirements for new male contraceptive development and provide and grade updated, evidence-based recommendations from the European Society of Andrology (EAA) and the American Society of Andrology (ASA).

METHODS

An expert panel of academicians appointed by the EAA and the ASA generated a consensus guideline according to the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) system.

RESULTS

Sixty evidence-based and graded recommendations were produced on couple-centered communication, behaviors, barrier methods, semen analysis and contraceptive efficacy, physical agents, surgical methods, actions before initiating male contraception, hormonal methods, non-hormonal methods, vaccines, and social and ethical considerations.

CONCLUSION

As gender roles transform and gender equity is established in relationships, the male contribution to family planning must be facilitated. Efficient and safe male-directed methods must be evaluated and introduced into clinical practice, preferably reversible, either hormonal or non-hormonal. From a future perspective, identifying new hormonal combinations, suitable testicular targets, and emerging vas occlusion methods will produce novel molecules and products for male contraception.

Design of an international male contraceptive efficacy trial using a self-administered daily transdermal gel containing testosterone and segesterone acetate (Nestorone)

Injectable male hormonal contraceptives are effective for preventing pregnancy in clinical trials; however, users may prefer to avoid medical appointments and injections. A self-administered transdermal contraceptive gel may be more acceptable for long-term contraception. Transdermal testosterone gels are widely used to treat hypogonadism and transdermal administration may have utility for male contraception; however, no efficacy data from transdermal male hormonal contraceptive gel are available. We designed and are currently conducting an international, multicenter, open-label study of self-administration of a daily combined testosterone and segesterone acetate (Nestorone) gel for male contraception. The transdermal approach to male contraception raises novel considerations regarding adherence with the daily gel, as well as concern about the potential transfer of the gel and the contraceptive hormones to the female partner. Enrolled couples are in committed relationships. Male partners have baseline normal spermatogenesis and are in good health; female partners are regularly menstruating and at risk for unintended pregnancy. The study's primary outcome is the rate of pregnancy in couples during the study's 52-week efficacy phase. Secondary endpoints include the proportion of male participants suppressing sperm production and entering the efficacy phase, side effects, hormone concentrations in male participants and their female partners, sexual function, and regimen acceptability. Enrollment concluded on November 1, 2022, with 462 couples and enrollment is now closed. This report outlines the strategy and design of the first study to examine the contraceptive efficacy of a self-administered male hormonal contraceptive gel. The results will be presented in future reports. IMPLICATIONS: The development of a safe, effective, reversible male contraceptive would improve contraceptive options and may decrease rates of unintended pregnancy. This manuscript outlines the study design and analysis plan for an ongoing large international trial of a novel transdermal hormone gel for male contraception. Successful completion of this and future studies of this formulation may lead to the approval of a male contraceptive.

Daily Oral Administration of the Novel Androgen 11β-MNTDC Markedly Suppresses Serum Gonadotropins in Healthy Men

BACKGROUND

11β-methyl-19-nortestosterone (11β-MNT) is a modified testosterone (T) with androgenic and progestational activity. A single oral dose of the prodrug, 11β-MNT dodecylcarbonate (11β-MNTDC), was well tolerated in healthy men.

METHODS

We conducted a randomized, double-blind study at 2 academic medical centers. 42 healthy men (18-50 years) were randomized to receive oral placebo or 11β-MNTDC, 200 or 400 mg daily, for 28 consecutive days. Primary outcome (safety and tolerability) measures were assessed twice per week. Subjects underwent serial blood sampling over 24 hours on days 1 and 28 to assess secondary outcomes: pharmacokinetics (serum drug concentrations); pharmacodynamics of 11β-MNTDC (serum sex steroids and gonadotropins); and mood and sexual function (via validated questionnaires).

RESULTS

There were no serious adverse events. No participants discontinued because of an adverse event or laboratory test abnormality. 11β-MNTDC resulted in a dose-related increase in serum 11β-MNTDC and 11β-MNT concentrations sustained over 24 hours. Administration of 11β-MNTDC resulted in a marked suppression of serum gonadotropins, T, calculated free T, estradiol, and SHBG over the treatment period (P < 0.01). Adverse effects that may be related to 11β-MNTDC included weight gain, acne, headaches, fatigue, and mild mood changes, with 5 men reporting decreased libido and 3 decreased erectile/ejaculatory function. Serum low-density lipoprotein cholesterol, weight (~2 kg), hematocrit, and hemoglobin increased and serum high-density lipoprotein cholesterol decreased in both 11β-MNTDC groups.

CONCLUSION

Daily oral 11β-MNTDC for 28 days in healthy men markedly suppressed serum gonadotropin and T concentrations without serious adverse effects. These results warrant further evaluation of 11β-MNTDC as a potential male oral contraceptive.

Combined nestorone-testosterone gel suppresses serum gonadotropins to concentrations associated with effective hormonal contraception in men

BACKGROUND

Novel male-based contraceptives are needed to broaden family planning choices. A progestin, Nestorone^® (Nes) gel, plus a testosterone (T) gel suppresses sperm concentrations to levels associated with effective contraception in normal men. However, administration of two gels on different parts of the body daily is impractical.

OBJECTIVE

Compare the effectiveness of daily application of a single, combined 8.3 mg Nes-62.5 mg T gel (Nes-T) vs. 62.7 mg T gel to suppress serum FSH and LH concentrations to ≤1.0 IU/L (a threshold associated with suppression of sperm concentrations to ≤1 million and effective contraception) and to compare the pharmacokinetics of serum Nes and T concentrations between the gel groups.

DESIGN

We conducted a 28-day, double-blind, controlled trial of 44 healthy men randomized to daily Nes-T or T gel with measurement of hormones at baseline, treatment, and recovery and during 24-h pharmacokinetic studies on days 1 and 28 of treatment.

RESULTS

Of the subjects who met pre-defined inclusion criteria, 84% of the Nes-T group suppressed serum gonadotropin concentrations to ≤1.0 IU/L at days 21-28 vs. 16.7% in the T group (p < 0.001). On day 1, Nes concentrations rose significantly above baseline by 2 h and continued to rise up to 24 h after Nes-T gel application. Nes concentrations were not detectable in the T group. Serum total T concentrations rose and were significantly higher in the T gel group compared to the Nes-T group at 24 h on day 1 and days 11, 14, and 21 (p < 0.01). There were no serious adverse events in either group. About 80% of the subjects reported satisfaction with both gels.

CONCLUSION

Daily Nes-T gel effectively and safely suppresses serum gonadotropins and is acceptable to most men. It should be studied further in efficacy trials of hormonal male contraception.

Safety and Pharmacokinetics of Single-Dose Novel Oral Androgen 11β-Methyl-19-Nortestosterone-17β-Dodecylcarbonate in Men

Context

11β-Methyl-19-nortestosterone-17β-dodecylcarbonate (11β-MNTDC) is an orally bioavailable prodrug of 11β-methyl-19-nortestosterone (11β-MNT) with androgenic and progestational activity.

Objectives

(i) Quantify 11β-MNT binding to androgen and progesterone receptors. (ii) Evaluate safety, tolerability, and serum gonadotropin and testosterone suppression by 11β-MNTDC in men.

Design and Setting

(i) In vitro receptor binding and transactivation studies and (ii) randomized, double-blind, placebo-controlled single-dose, dose-escalating phase I study at two academic medical centers.

Participants and Intervention

Twelve healthy male volunteers were randomized (five active, one placebo) to escalating single oral doses (100, 200, 400, and 800 mg) of 11β-MNTDC or placebo given with or without food.

Main Outcome Measures

(i) In vitro 11β-MNT/11β-MNTDC human receptor binding and transactivation and (ii) safety and tolerability, pharmacokinetics, and quantification of serum gonadotropin and testosterone concentrations for 24 hours following dosing.

Results

11β-MNT avidly binds and activates human androgen and progesterone receptors, but 11β-MNTDC has minimal activity. Single oral doses of 11β-MNTDC were well tolerated without serious adverse events. Administration of 11β-MNTDC with food markedly increased average 11β-MNTDC and 11β-MNT serum concentrations (P < 0.001 for all doses) compared with fasting with a significant dose-related effect on average serum drug concentrations (P < 0.0001). The 200-, 400-, and 800-mg doses significantly suppressed average serum testosterone concentrations (P < 0.05).

Conclusions

A single, oral dose of 11β-MNTDC up to 800 mg administered with food is safe and well tolerated in healthy men. The active drug 11β-MNT has androgenic and progestational activity, rapidly suppresses serum testosterone, and is a promising candidate for an effective once-daily oral male hormonal contraceptive.

Effects of 28 Days of Oral Dimethandrolone Undecanoate in Healthy Men: A Prototype Male Pill

CONTEXT

Dimethandrolone (DMA) has androgenic and progestational activity. Single oral doses of DMA undecanoate (DMAU) were well tolerated and reversibly suppressed serum LH and testosterone (T) in men.

OBJECTIVE

Assess safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of oral DMAU.

DESIGN

Double-blind, randomized, placebo-controlled study.

SETTING

Two academic medical centers.

PARTICIPANTS

Healthy men (18 to 50 years).

INTERVENTIONS

One hundred men received DMAU [0, 100, 200, or 400 mg, formulated in castor oil/benzyl benzoate (C) or powder (P)] for 28 days. Subjects underwent 24-hour PK sampling on days 1 and 28 and twice weekly ambulatory visits throughout treatment.

MAIN OUTCOME MEASURES

Primary outcomes were safety and tolerability parameters (vitals, laboratory data, mood, and sexual function scores) and adverse events. Secondary outcomes were drug PK profiles and PD effects (serum LH, FSH, and sex hormones).

RESULTS

Eighty-two subjects completed the study and were included in the analysis. There were no serious adverse events. No clinically significant changes developed in safety laboratory parameters. A significant dose effect was seen for weight, hematocrit, high-density lipoprotein cholesterol, corrected QT interval, and sexual desire. Serum 24-hour average concentrations of DMAU and DMA showed dose-related increases (P < 0.001). All six subjects in the P400 group and 12 of 13 subjects in the C400 group achieved marked suppression of LH and FSH (<1.0 IU/L) and serum T (<50 ng/dL).

CONCLUSIONS

Daily oral administration of DMAU for 28 days in healthy men is well tolerated. Doses of ≥200 mg markedly suppress serum T, LH, and FSH. These results support further testing of DMAU as a male contraceptive.

Preventing secondary exposure to women from men applying a novel nestorone/testosterone contraceptive gel

BACKGROUND

Testosterone (T)/Nestorone (NES) combination gel is a potential transdermal male contraceptive that suppresses gonadotropins and spermatogenesis. Transfer of transdermal T from men to women can be prevented by washing or covering application sites with clothing.

OBJECTIVES

We hypothesized that showering or wearing a shirt over gel application sites would prevent secondary exposure of T and NES to a woman after close skin contact.

MATERIALS AND METHODS

Twelve healthy male and 12 healthy female participants were recruited. Men applied T/NES 62 mg/8 mg gel to their shoulders and upper arms. Two hours after application, female partners rubbed the application site for 15 min. Exposure in the female partner was assessed under three conditions: a shirt covered the application site; the man showered prior to skin contact; or without intervention to reduce transfer. Serum T and NES concentrations were measured by LC-MS/MS in serial blood samples for 24 h after gel exposure.

MAIN OUTCOMES

Change in female serum T and NES levels as measured by average concentration over 24 h (C_avg ).

RESULTS

Median female serum T C_avg was 23.9 ng/dL (interquartile range, 19.3, 33.9) with the shirt barrier and 26.7 ng/dL (20.7, 33.9) after showering, which was higher than baseline 20.9 ng/dL (16.7, 25.0), both p < 0.03) but lower than without intervention (58.2 ng/dL [30.9, 89.1], both p < 0.01). Female serum NES C_avg and maximum concentration were below the lower limit of quantification with the shirt barrier and after showering, but increased without intervention in six of 12 women (maximum concentration <60 pg/mL). Men had lower average serum NES levels after showering (47 pg/ml [20, 94] compared to no intervention (153.3 pg/mL [51, 241], p < 0.02).

CONCLUSION

Secondary transfer of T and NES occurs after intensive skin contact with the gel application site. Secondary transfer is decreased by a shirt barrier or showering before contact.

Comparison of the single dose pharmacokinetics, pharmacodynamics, and safety of two novel oral formulations of dimethandrolone undecanoate (DMAU): a potential oral, male contraceptive

Dimethandrolone (DMA, 7α,11β-dimethyl-19-nortestosterone) has both androgenic and progestational activities, ideal properties for a male hormonal contraceptive. In vivo, dimethandrolone undecanoate (DMAU) is hydrolyzed to DMA. We showed previously that single oral doses of DMAU powder in capsule taken with food are well tolerated and effective at suppressing both LH and testosterone (T), but absorption was low. We compared the pharmacokinetics and pharmacodynamics of two new formulations of DMAU, in castor oil and in self-emulsifying drug delivery systems (SEDDS), with the previously tested powder formulation. DMAU was dosed orally in healthy adult male volunteers at two academic medical centers. For each formulation tested in this double-blind, placebo-controlled study, 10 men received single, escalating, oral doses of DMAU (100, 200, and 400 mg) and two subjects received placebo. All doses were evaluated for both fasting and with a high fat meal. All three formulations were well tolerated without clinically significant changes in vital signs, blood counts, or serum chemistries. For all formulations, DMA and DMAU showed higher maximum (p < 0.007) and average concentrations (p < 0.002) at the 400 mg dose, compared with the 200 mg dose. The powder formulation resulted in a lower conversion of DMAU to DMA (p = 0.027) compared with both castor oil and SEDDS formulations. DMAU in SEDDS given fasting resulted in higher serum DMA and DMAU concentrations compared to the other two formulations. Serum LH and sex hormone concentrations were suppressed by all formulations of 200 and 400 mg DMAU when administered with food, but only the SEDDS formulation was effectively suppressed serum T when given fasting. We conclude that while all three formulations of oral DMAU are effective and well tolerated when administered with food, DMAU in oil and SEDDS increased conversion to DMA, and SEDDS may have some effectiveness when given fasting. These properties might be advantageous for the application of DMAU as a male contraceptive.

Testicular fine-needle aspiration for the assessment of intratesticular hormone concentrations

Measurement of intratesticular sex steroid concentrations in men informs both the development of male hormonal contraceptives and the understanding of male infertility. Given the challenges of using invasive techniques to measure testicular hormone physiology, our group has used a minimally-invasive fine-needle aspiration technique to measure intratesticular hormones in normal healthy men. Herein, we present a post-hoc analysis of the safety and efficacy of testicular fine-needle aspiration (FNA) completed as part of six clinical trials. From 2001 through 2011, a total of 404 procedures were conducted among 163 research volunteers, 85.9% of which were successful in obtaining sufficient fluid for the measurement of intratesticular steroid concentrations. Pain was the most common side effect, with 36.8% of procedures associated with moderate procedural pain and 4.7% with severe procedural pain. Postprocedural pain was uncommon and abated within a few days. Mild local bruising occurred with 14.9% of procedures. Two serious adverse events (0.5%) required surgical intervention. The risk of an adverse event was not associated with age, body mass index, testicular size, or the volume of fluid aspirated. Testicular FNA to obtain fluid for measurement of intratesticular steroid concentrations frequently causes mild to moderate procedural pain, but serious adverse events occur rarely. Testicular FNA has been instrumental for defining human intratesticular hormone physiology and is a minimally-invasive, safe, effective method for obtaining fluid for research on testicular physiology and pathology.

Male hormonal contraception: looking back and moving forward

Despite numerous contraceptive options available to women, approximately half of all pregnancies in the United States and worldwide are unplanned. Women and men support the development of reversible male contraception strategies, but none have been brought to market. Herein we review the physiologic basis for male hormonal contraception, the history of male hormonal contraception development, currents agents in development as well as the potential risks and benefits of male hormonal contraception for men.

Acceptability of a transdermal gel-based male hormonal contraceptive in a randomized controlled trial

OBJECTIVE

Fifty percent of pregnancies in the United States are unintended despite numerous contraceptive methods available to women. The only male contraceptive methods, vasectomy and condoms, are used by 10% and 16% of couples, respectively. Prior studies have shown efficacy of male hormonal contraceptives in development, but few have evaluated patient acceptability and potential use if commercially available. The objective of this study is to determine if a transdermal gel-based male hormonal contraceptive regimen, containing testosterone and Nestorone® gels, would be acceptable to study participants as a primary contraceptive method.

STUDY DESIGN

As part of a three-arm, 6-month, double-blind, randomized controlled trial of testosterone and nestorone gels at two academic medical centers, subjects completed a questionnaire to assess the acceptability of the regimen. Of the 99 men randomized, 79 provided data for analysis.

RESULTS

Overall, 56% (44/79) of men were satisfied or extremely satisfied with this gel-based method of contraception, and 51% (40/79) reported that they would recommend this method to others. One third of subjects (26/79) reported that they would use this as their primary method of contraception if it were commercially available today. However, men with concerns about sexually transmitted disease were significantly less satisfied than men without such concerns (p=0.03).

CONCLUSIONS

A majority of the men who volunteered to participate in this trial of an experimental male hormonal contraceptive were satisfied with this transdermal male hormonal contraceptive. If commercially available, a combination of topical nesterone and testosterone gels could provide a reversible, effective method of contraception that is appealing to men.

IMPLICATIONS

A substantial portion of men report they would use this transdermal male contraceptive regimen if commercially available. This method would provide a novel, reversible method of contraception for men, whose current choices are limited to condoms and vasectomy.

Single, escalating dose pharmacokinetics, safety and food effects of a new oral androgen dimethandrolone undecanoate in man: a prototype oral male hormonal contraceptive

The novel androgen, dimethandrolone (DMA) has both androgenic and progestational activities, properties that may maximize gonadotropin suppression. We assessed the pharmacokinetics of dimethandrolone undecanoate (DMAU), an orally bioavailable, longer acting ester of DMA, for male contraceptive development. Our objective was to examine the safety and pharmacokinetics of single, escalating doses of DMAU (powder in capsule formulation) administered orally with or without food in healthy men. We conducted a randomized, double-blind Phase 1 study. For each dose of DMAU (25-800 mg), 10 male volunteers received DMAU and two received placebo at two academic medical centres. DMAU was administered both fasting and after a high-fat meal (200-800 mg doses). Serial serum samples were collected over 24 h following each dose. DMAU was well tolerated without significant effects on vital signs, safety laboratory tests or electrocardiograms. When administered while fasting, serum DMA (active compound) was detectable in only 4/10 participants after the 800 mg dose. When administered with a 50% fat meal, serum DMA was detectable in all participants given 200 mg DMAU and showed a dose-incremental increase up to 800 mg, with peak levels 4-8 h after taking the dose. Serum gonadotropins and sex hormone concentrations were significantly suppressed 12 h after DMAU administration with food at doses above 200 mg. This first-in-man study demonstrated that a single, oral dose of DMAU up to 800 mg is safe. A high-fat meal markedly improved DMAU/DMA pharmacokinetics.

Characteristics associated with suppression of spermatogenesis in a male hormonal contraceptive trial using testosterone and Nestorone(®) gels

Development of a male hormonal contraceptive has been challenging ascribable to the failure to adequately suppress spermatogenesis in 5-10% of men. Methods to identify incomplete suppressors early in treatment might identify men most responsive to male hormonal contraceptives. We hypothesized that serum hormone and gonadotropin concentrations after 4 weeks of transdermal treatment with testosterone and Nestorone in a contraceptive trial would be associated with suppression of sperm concentrations to <1 million/mL after 24 weeks. Indeed, luteinizing hormone or follicle-stimulating hormone concentrations greater than 1 IU/L after 4 weeks of transdermal testosterone/nestorone treatment were 97% sensitive for predicting failure to suppress spermatogenesis after 24 weeks of treatment. Serum nestorone concentrations were significantly associated with suppression, but serum testosterone concentrations were not. Early suppression of gonadotropins is associated with, but does not ensure, adequate suppression of spermatogenesis. This information may allow for rapid identification of non-responders in male hormonal contraceptive trials.

Androgen synthesis in the gonadotropin-suppressed human testes can be markedly suppressed by ketoconazole

CONTEXT

The concentration of intratesticular testosterone (IT-T) required for human spermatogenesis is unknown because spermatogenesis can persist despite the markedly reduced IT-T concentrations observed with LH suppression. Methods to lower IT-T further are needed to determine the relationship between IT-T and spermatogenesis.

OBJECTIVE

The objective of the study was to determine the effect of inhibiting the synthesis and metabolism of testosterone (T) on IT-T in gonadotropin-suppressed human testes.

DESIGN/SETTING/PATIENTS

Forty normal men participated in a blinded, placebo-controlled, randomized trial at an academic center. INTERVENTION/OUTCOME MEASURES: All men were first administered the GnRH antagonist acyline to suppress LH. Forty-eight hours after acyline administration, subjects were randomly assigned to placebo, ketoconazole (to inhibit T synthesis) at 400 or 800 mg, dutasteride (to inhibit T metabolism) 2.5 mg, or anastrazole (to inhibit T metabolism) 1 mg, daily for 7 days (n = 8/group). Intratesticular steroid concentrations were measured 48 hours after acyline administration alone and again after 7 days of combination treatment.

RESULTS

After 7 days of combination treatment, the median IT-T (25th, 75th percentile) in the placebo group was 14 (8.0, 21.2) ng/mL. IT-T was reduced to 3.7 (2.5, 7.1) ng/mL in the ketoconazole 400 mg group and 1.7 (0.8, 4.0) ng/mL in the ketoconazole 800 mg group (P < .001 vs placebo for both comparisons). IT-T concentrations in the dutasteride and anastrazole groups were similar to placebo.

CONCLUSION

Combining inhibition of steroidogenesis with gonadotropin suppression lowers IT-T more than gonadotropin suppression alone. This combination might be useful to determine the minimum IT-T concentration necessary for human spermatogenesis, information essential for developing male hormonal contraceptives.

Intratesticular Testosterone Concentrations Comparable With Serum Levels Are Not Sufficient to Maintain Normal Sperm Production in Men Receiving a Hormonal Contraceptive Regimen

Intratesticular testosterone (ITT) is thought to play a key role in the control of spermatogenesis in man but is rarely measured. The purposes of this study were 1) to examine the relationship between intratesticular fluid and serum testosterone (T) at baseline and during treatment with a contraceptive regimen known to suppress spermatogenesis and 2) to measure intratesticular fluid androgenic bioactivity. Seven men received 6 months of T enanthate (TE) 100 mg weekly intramuscularly plus levonorgestrel (LNG) 62.5 or 31.25 microg orally daily. Testicular fluid was obtained by percutaneous aspiration at baseline and during month 6. Mean luteinizing hormone (LH) was suppressed 98% from 3.79 +/- 0.80 IU/L at baseline to 0.08 +/- 0.03 IU/L. Mean follicle stimulating hormone (FSH) was suppressed 97%, from 3.29 +/- 0.67 IU/L to 0.10 +/- 0.03 IU/L. Mean serum T levels were similar before (22.8 +/- 1.9 nmol/L) and during treatment (28.7 +/- 2.0 nmol/L) (P = .12). ITT (822 +/- 136 nmol/L) was approximately 40x higher than serum T (P < .001) at baseline. ITT was suppressed 98% during treatment to 13.1 +/- 4.5 nmol/L, a level similar to baseline serum T (P = .08) but significantly lower than on-treatment serum T (P = .01). At baseline, intratesticular fluid androgenic bioactivity (583 +/- 145 nmol/L) was 70% of the ITT concentration measured by radioimmunoassay. Intratesticular androgenic bioactivity was suppressed 93% to 40 +/- 22 nmol/L (P < .01) during treatment, but was 3x higher than ITT (13.1 +/- 4.5 nmol/L). Sperm counts declined from 65 +/- 15 million/mL to 1.3 +/- 1.3 million/mL. In summary, TE plus LNG dramatically suppressed ITT (98%) and intratesticular androgenic bioactivity (93%) to levels approximating those in serum. ITT levels comparable with serum T were insufficient to support normal spermatogenesis. Intratesticular androgenic bioactivity was higher than ITT during treatment, suggesting that other androgens may be prevalent in the low-ITT environment.

Male Hormonal Contraception: Suppression of Spermatogenesis by Injectable Testosterone Undecanoate Alone or With Levonorgestrel Implants in Chinese Men

Monthly injections of testosterone undecanoate (TU) act as a male contraceptive by reversibly suppressing spermatogenesis to azoospermia or severe oligoazoospermia in 95% of Chinese men. In 5% of Chinese men, however, monthly TU administered alone fails to suppress spermatogenesis into contraceptive ranges, or sperm "rebound," leading to occurrences of pregnancy during treatment. Since combinations of progestins and androgens are associated with greater degrees of sperm suppression in white men, we hypothesized that the combination of TU and the progestin levonorgestrel (LNG) would result in improved spermatogenic suppression in Chinese men. Sixty-two healthy Chinese men were randomly assigned to one of the following 3 regimens: group I (n = 21) received 4 LNG rods (75 mg each), which were followed 4 weeks later by 500 mg of TU by intra-muscular (IM) injection every 8 weeks for 24 weeks; group II (n = 20) received 4 LNG implants, which were followed 4 weeks later by 1000 mg of TU by IM injection every 8 weeks for 24 weeks; and group III (n = 21) received TU 1000 mg by IM injection every 8 weeks for 24 weeks. Sperm counts, serum testosterone (T), luteinizing hormone, follicle-stimulating hormone, and LNG were measured every 2 weeks before, during, and after treatment. During treatment, group II demonstrated a trend toward a greater attainment of azoospermia than groups I and III (90% vs 62% [group I] vs 67% [group III]; P =.09). Attainments of either azoospermia or oligozoospermia (sperm density, <3 x 10(6)/mL) were 95%, 100%, and 86% for groups I, II, and III, respectively (P >.05 for comparisons between groups). Spermatogenesis in all subjects returned to the normal range after the implants were removed. No serious adverse events and no significant changes in serum chemistry occurred during the study. These results demonstrate that the combination of IM injections of high-dose TU every 2 months and LNG implants is associated with marked suppression of spermatogenesis in Chinese men. The combination of high-dose TU every 2 months and LNG implants is a promising candidate for future large-scale efficacy studies of hormonal male contraception in Chinese men.

Contraception for men: a breakthrough new approach

There has not been a new reversible contraceptive for men since the development of the condom, centuries ago. Matzuk et al. describe a new molecular approach using administration of a small molecule to directly and reversibly inhibit spermatogenesis in mice by blocking the function of a testicular bromodomain without apparent adverse effect on the organism or offspring.

Serum insulin-like factor 3 is highly correlated with intratesticular testosterone in normal men with acute, experimental gonadotropin deficiency stimulated with low-dose human chorionic gonadotropin: a randomized, controlled trial

OBJECTIVE

To study the potential role for using serum biomarkers, including insulin-like factor 3 (INSL3), 17α-hydroxyprogesterone, antimüllerian hormone, and inhibin B, as correlates of intratesticular T (IT-T) concentrations in men.

DESIGN

Prospective, randomized, controlled trial.

SETTING

University-based medical center.

PATIENT(S)

Thirty-seven healthy men aged 18-50 years.

INTERVENTION(S)

All men received the GnRH antagonist acyline, plus very low doses of hCG (0 IU, 15 IU, 60 IU, or 125 IU) SC every other day or 7.5 g T gel daily (75 mg delivered). The IT-T concentrations obtained by percutaneous testicular aspiration with simultaneous serum protein and steroid concentrations were measured at baseline and after 10 days of treatment.

MAIN OUTCOME MEASURE(S)

Intratesticular and serum hormone and gonadotropin concentrations.

RESULT(S)

After 10 days of gonadotropin suppression, serum INSL3 decreased by more than 90% and correlated highly with IT-T concentrations. In contrast, serum inhibin B, antimüllerian hormone, and 17α-hydroxyprogesterone did not correlate with IT-T. Serum INSL3 increased with the dose of hCG administered and returned to baseline after treatment.

CONCLUSION(S)

Serum INSL3 correlates highly with IT-T and serum T concentrations during acute gonadotropin suppression in men. Human chorionic gonadotropin stimulates dose-dependent increases in INSL3 and IT-T in healthy men and might be a useful biomarker of IT-T concentration in some clinical settings.

CLINICAL TRIAL REGISTRATION NUMBER

NCT# 00839319.

Androgen receptor gene expression in the rat central nervous system: Evidence for two mRNA transcripts

Androgen receptor (AR) gene expression in the central nervous system (CNS) and peripheral tissues of male rats was examined using cDNA probes to measure AR mRNA by RNA (Northern) blot analysis and by in situ hybridization. Using a probe from the 5' untranslated region of the rat cDNA (AR-1), a single mRNA species of approximately 11 kb was seen in Northern blots of poly(A)(+) RNA from reproductive tissues, kidney, liver, and muscle. Using a probe from the 5' end of the coding region (AR-2), in addition to the 11-kb band, a novel transcript was seen in whole brain at about 9.3 kb. In poly(A)(+) RNA from dissected brain regions, the 9.3-kb transcript was predominant in the cortex, cerebellum, and brain stem, while in the hippocampus, both transcripts were expressed to a similar degree. AR mRNA levels increased two- to threefold in the prostate on Days 1 and 3 following castration but no significant change was seen in either CNS transcript in whole brain or cortex. Specific in situ hybridization of an (35)S-labeled AR-2 riboprobe was observed in brain regions known to bind radiolabeled androgens. We conclude that two AR RNA species exist in the adult male rat which differ in their 5' untranslated region and that the relative proportion of the two species varies between brain regions. In contrast to observations in the prostate, AR gene expression in the cerebral cortex is not regulated in the short term by androgen withdrawal.

A new combination of testosterone and nestorone transdermal gels for male hormonal contraception

CONTEXT

Combinations of testosterone (T) and nestorone (NES; a nonandrogenic progestin) transdermal gels may suppress spermatogenesis and prove appealing to men for contraception.

OBJECTIVE

The objective of the study was to determine the effectiveness of T gel alone or combined with NES gel in suppressing spermatogenesis.

DESIGN AND SETTING

This was a randomized, double-blind, comparator clinical trial conducted at two academic medical centers.

PARTICIPANTS

Ninety-nine healthy male volunteers participated in the study.

INTERVENTIONS

Volunteers were randomized to one of three treatment groups applying daily transdermal gels (group 1: T gel 10 g+NES 0 mg/placebo gel; group 2: T gel 10 g+NES gel 8 mg; group 3: T gel 10 g+NES gel 12 mg).

MAIN OUTCOME VARIABLE

The main outcome variable of the study was the percentage of men whose sperm concentration was suppressed to 1 million/ml or less by 20-24 wk of treatment.

RESULTS

Efficacy data analyses were performed on 56 subjects who adhered to the protocol and completed at least 20 wk of treatment. The percentage of men whose sperm concentration was 1 million/ml or less was significantly higher for T+NES 8 mg (89%, P<0.0001) and T+NES 12 mg (88%, P=0.0002) compared with T+NES 0 mg group (23%). The median serum total and free T concentrations in all groups were maintained within the adult male range throughout the treatment period. Adverse effects were minimal in all groups.

CONCLUSION

A combination of daily NES+T gels suppressed sperm concentration to 1 million/ml or less in 88.5% of men, with minimal adverse effects, and may be further studied as a male transdermal hormonal contraceptive.

Impact of male hormonal contraception on prostate androgens and androgen action in healthy men: a randomized, controlled trial

CONTEXT

Male hormonal contraception (MHC) combines hypothalamic-pituitary-gonadal axis blockade with exogenous androgen delivery to maintain extragonadal androgen end-organ effects. Concern exists that MHC may adversely impact prostate health.

OBJECTIVE

The objective of the study was to determine the molecular impact of MHC on intraprostatic androgen concentrations and androgen action.

DESIGN

This was a single-blind, randomized, placebo-controlled study.

SETTING

The study was conducted at an academic medical center.

PARTICIPANTS

32 healthy men aged 25-55 yr participated in the study.

INTERVENTION

Interventions included placebo, daily transdermal testosterone (T) (T-gel), T-gel + depomedroxyprogesterone acetate (T+DMPA), or T-gel + dutasteride daily (T+D) for 12 wk, and prostate biopsy during treatment wk 10.

MAIN OUTCOME MEASURES

Serum and prostate androgen concentrations and prostate epithelial-cell gene expression were measured.

RESULTS

Thirty men completed the study. Serum T levels were significantly increased in T-gel and T+D groups compared with baseline (P < 0.05) but were decreased with the addition of DMPA. Intraprostatic androgens were no different from placebo with T-gel treatment. Addition of DMPA to T resulted in 40% lower intraprostatic dihydrotestosterone (DHT) concentration (P = 0.0273 vs. placebo), whereas combining dutasteride with T resulted in a 90% decrease in intraprostatic DHT (P = 0.0012), 11-fold increased intraprostatic T (P = 0.0011), and 7-fold increased intraprostatic androstenedione (P = 0.0011). Significant differences in global or androgen-regulated prostate epithelial-cell gene expression were not observed. Androgen-regulated gene expression correlated with epithelial-cell androgen receptor and prostatic DHT in placebo, T-gel, and T+DMPA arms and with T and androstenedione levels in the T+D arm.

CONCLUSIONS

MHC regimens do not markedly alter gene expression in benign prostate epithelium, suggesting they may not alter risk of prostate disease. Longer-term studies examining the impact of MHC on prostate health are needed.

Pharmacokinetics of modified slow-release oral testosterone over 9 days in normal men with experimental hypogonadism

Oral administration of testosterone has potential use for the treatment of hypogonadism. We have recently demonstrated that a novel formulation of oral testosterone transiently normalized serum testosterone in a single-dose pharmacokinetic study. In this report, we present the steady-state pharmacokinetics of this formulation. Twelve healthy young men were rendered hypogonadal with the gonadotropin-releasing hormone antagonist acyline (300 μg/kg subcutaneously) and administered 300 mg of oral testosterone 3 times daily for 9 days. Serum testosterone, dihydrotestosterone (DHT), estradiol, and sex hormone-binding globulin (SHBG) were measured before and 1, 2, 4, 5, 6, 8, 10, 11, 12, 14, 16, and 24 hours on the first and ninth day of dosing. Before testosterone administration, all men had serum testosterone under 75 ng/dL. Over day 1, the 24-hour average (geometric mean [%CV]) serum total testosterone was 378 (45) ng/dL. This decreased to 315 (41) ng/dL after 9 days of continuous treatment (P = .1 compared with day 1). The 24-hour average serum SHBG was 27 (46) nmol/L on day 1 and was significantly reduced to 19 (47) nmol/L by day 9 (P < .01). As a result, the calculated free testosterone values were similar between day 1 and day 9: 8.7 (43) and 8.3 (37) ng/dL, respectively. DHT was in the reference range and estradiol was slightly below on day 9. Oral testosterone (300 mg) dosed 3 times daily normalized serum testosterone in men with experimentally induced hypogonadism after 9 days of dosing and significantly suppressed SHBG. This formulation of oral testosterone may have efficacy for the treatment of testosterone deficiency.

The effect of gonadotropin withdrawal and stimulation with human chorionic gonadotropin on intratesticular androstenedione and DHEA in normal men

INTRODUCTION

Concentrations of intratesticular (IT) testosterone (T) are known to be 100-200 times those of serum T; however, the IT concentrations of T's precursors, their testicular to serum gradients, gonadotropin dependence, and response to stimulation with human chorionic gonadotropin (hCG) have not been studied in detail. We hypothesized that serum and IT androstenedione (ADD) and IT dehydroepiandrosterone (DHEA) would be significantly suppressed by the administration of a GnRH antagonist and increased when stimulated by hCG, without a similar suppression of serum DHEA.

METHODS

We suppressed gonadotropins in 23 normal men with the GnRH antagonist acyline and randomly assigned them to one of four doses of hCG, 0, 15, 60, or 125 IU sc every other day for 10 d. Blood and IT fluid for the measurement of serum and IT hormones were obtained at baseline and after 10 d of treatment.

RESULTS

Baseline IT ADD [median (25th, 75th percentile)] was 629 (308, 860) nmol/liter, and IT DHEA was 564 (411, 879) nmol/liter, which were 175 and 27 times higher than their respective serum concentrations. IT ADD and IT DHEA were suppressed by 98 and 82%, respectively, by acyline and significantly increased with hCG administration. Likewise, serum ADD was suppressed by 50%, but serum DHEA was unchanged.

DISCUSSION

ADD and DHEA are highly concentrated within the human testes compared with serum. Serum and IT ADD and IT DHEA are markedly suppressed with GnRH administration and stimulated by hCG, but serum DHEA is not, suggesting that most circulating DHEA is not of testicular origin.

Dose-dependent increase in intratesticular testosterone by very low-dose human chorionic gonadotropin in normal men with experimental gonadotropin deficiency

CONTEXT AND OBJECTIVE

In men with infertility secondary to gonadotropin deficiency, treatment with relatively high dosages of human chorionic gonadotropin (hCG) stimulates intratesticular testosterone (IT-T) biosynthesis and spermatogenesis. Previously we found that lower dosages of hCG stimulated IT-T to normal. However, the minimal dose of hCG needed to stimulate IT-T and the dose-response relationship between very low doses of hCG and IT-T and serum testosterone in normal men is unknown.

DESIGN, SETTING, PATIENTS, AND INTERVENTION

We induced experimental gonadotropin deficiency in 37 normal men with the GnRH antagonist acyline and randomized them to receive one of four low doses of hCG: 0, 15, 60, or 125 IU sc every other day or 7.5 g daily testosterone gel for 10 d. Testicular fluid was obtained by percutaneous aspiration for steroid measurements at baseline and after 10 d of treatment and correlated with contemporaneous serum hormone measurements.

RESULTS

Median (25th, 75th percentile) baseline IT-T was 2508 nmol/liter (1753, 3502 nmol/liter). IT-T concentrations increased in a dose-dependent manner with very low-dosage hCG administration from 77 nmol/liter (40, 122 nmol/liter) to 923 nmol/liter (894, 1017 nmol/liter) in the 0- and 125-IU groups, respectively (P<0.001). Moreover, serum hCG was significantly correlated with both IT-T and serum testosterone (P<0.01).

CONCLUSION

Doses of hCG far lower than those used clinically increase IT-T concentrations in a dose-dependent manner in normal men with experimental gonadotropin deficiency. Assessment of IT-T provides a valuable tool to investigate the hormonal regulation of spermatogenesis in man.

Pharmacokinetics of 2 novel formulations of modified-release oral testosterone alone and with finasteride in normal men with experimental hypogonadism

Oral administration of testosterone might be useful for the treatment of testosterone deficiency. However, current "immediate-release" formulations of oral testosterone exhibit suboptimal pharmacokinetics, with supraphysiologic peaks of testosterone and its metabolite, dihydrotestosterone (DHT), immediately after dosing. To dampen these peaks, we have developed 2 novel modified-release formulations of oral testosterone designed to slow absorption from the gut and improve hormone delivery. We studied these testosterone formulations in 16 normal young men enrolled in a 2-arm, open-label clinical trial. Three hundred-mg and 600-mg doses of immediate-release and modified fast-release or slow-release formulations were administered sequentially to 8 normal men rendered hypogonadal by the administration of the gonadotropin-releasing hormone antagonist acyline. Blood for measurement of serum testosterone, DHT, and estradiol was obtained before and 0.5, 1, 2, 3, 4, 6, 8, 12, and 24 hours after each dose. A second group of 8 men was studied with the coadministration of 1 mg of the 5α-reductase inhibitor finasteride daily throughout the treatment period. Serum testosterone was increased with all formulations of oral testosterone. The modified slow-release formulation significantly delayed the postdose peaks of serum testosterone and reduced peak concentrations of serum DHT compared with the immediate-release formulation. The addition of finasteride further increased serum testosterone and decreased serum DHT. We conclude that the oral modified slow-release testosterone formulation exhibits superior pharmacokinetics compared with immediate-release oral testosterone both alone and in combination with finasteride. This formulation might have efficacy for the treatment of testosterone deficiency.

Serum LH correlates highly with intratesticular steroid levels in normal men

Sex steroids are essential for spermatogenesis; however, normal intratesticular concentrations of these hormones in man have not been extensively studied. To improve our understanding of intratesticular hormone concentrations, we performed bilateral testicular aspirations in a group of normal men, determined sex steroid concentrations within each testis, and compared these levels to serum hormone concentrations. Ten healthy human subjects aged 20-49 underwent bilateral testicular aspirations. Intratesticular hormone concentrations of testosterone, dihydrotestosterone (DHT), and estradiol were measured using liquid chromatography-tandem mass spectrometry. Intratesticular testosterone concentrations ranged from 119 to 1251 ng/mL, with a mean of 635 +/- 368 ng/mL. Intratesticular estradiol ranged from 0.41 to 3.9 ng/mL, with a mean of 2.4 +/- 1.3 ng/mL. Intratesticular DHT ranged from 1.1 to 7.9 ng/mL, with a mean of 3.5 +/- 3.2 ng/mL. Intratesticular testosterone and estradiol concentrations correlated highly with serum luteinizing hormone (LH; r = 0.87 and r = 0.70 respectively, P < .01). Intratesticular testosterone correlated highly with serum testosterone. Moreover, a significant correlation between the right and left testes was observed for testosterone (r = 0.82, P = .003), but not for estradiol or DHT. Intratesticular hormone concentrations can be safely assessed by testicular aspiration. Intratesticular testosterone and estradiol correlate highly with serum LH concentrations, and variation in serum LH accounts for most of the variation in intratesticular testosterone among men. In addition, intratesticular testosterone is highly correlated between testes in a given individual. Direct measurement of intratesticular testosterone will improve our understanding of the relationship between intratesticular sex steroids and spermatogenesis, and may have implications for the development of male hormonal contraception.

Combined transdermal testosterone gel and the progestin nestorone suppresses serum gonadotropins in men

CONTEXT

Testosterone (T) plus progestin combinations are the most promising hormonal male contraceptives. Nestorone (NES), a progestin without estrogenic or androgenic activity, when combined with T may be an excellent candidate for male contraception.

OBJECTIVE

Our objective was to determine the effect of transdermal NES gel alone or with T gel on gonadotropin suppression.

DESIGN AND SETTING

The randomized, unblinded clinical trial was conducted at two academic medical centers.

PARTICIPANTS

A total of 140 healthy male volunteers participated.

INTERVENTIONS

One hundred subjects were randomized initially (20 per group) to apply NES gel 2 or 4 mg, T gel 10 g, or T gel 10 g plus NES gel 2 or 4 mg daily for 20 d. Because only about half of the subjects in T plus NES 4 mg group suppressed serum gonadotropins to 0.5 IU/liter or less (suboptimal suppression), two additional groups of 20 men were randomized to apply daily T gel 10 g plus NES gel 6 or 8 mg.

MAIN OUTCOME VARIABLE

Suppression of serum LH and FSH concentrations to 0.5 IU/liter or less after treatment was the main outcome variable.

RESULTS

A total of 119 subjects were compliant with gel applications with few study-related adverse events. NES alone reduced gonadotropins significantly but less than T gel alone. Combined T gel 10g plus NES gel 6 or 8 mg suppressed both serum gonadotropins to 0.5 IU/liter or less in significantly more men than either gel alone.

CONCLUSION

Transdermal NES gel alone had gonadotropin suppression activity. Combined transdermal NES (6 or 8 mg) plus T gel demonstrated safe and effective suppression of gonadotropins, justifying a longer-term study of this combination for suppression of spermatogenesis.

Oral administration of the GnRH antagonist acyline, in a GIPET-enhanced tablet form, acutely suppresses serum testosterone in normal men: single-dose pharmacokinetics and pharmacodynamics

PURPOSE

GnRH analogs are useful for the treatment of prostate cancer, but require parenteral administration. The peptide GnRH antagonist acyline potently suppresses luteinizing hormone (LH) and testosterone in man; however, its clinical utility is limited by the requirement for frequent injections. The use of a proprietary enhancer system called GIPET, which is based on medium-chain fatty acids, facilitates the oral bioavailability of peptides. We hypothesized that GIPET enhancement would allow for the safe oral dosing of acyline for the treatment of prostate cancer.

METHODS

We enrolled eight healthy young men in a pharmacokinetic and pharmacodynamic study of 10, 20 and 40 mg doses of GIPET-enhanced oral acyline. Blood for measurement of serum LH, FSH, testosterone and acyline was obtained prior to each dose of GIPET-enhanced oral acyline and 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, 24 and 48 h after dosing.

RESULTS

Serum LH, FSH and serum testosterone were significantly suppressed by all doses of GIPET-enhanced oral acyline after 6 h, with suppression reaching a nadir 12 h after dosing. In addition, the 20 and 40 mg doses demonstrated sustained suppression of testosterone for 12-24 h. All hormone concentrations returned to normal 48 h after administration. There were no treatment-related serious adverse events, and laboratory assessments, including liver function tests and creatinine, were unaffected by treatment.

CONCLUSIONS

Oral administration of GIPET-enhanced acyline significantly suppresses testosterone and gonadotropins in normal men without untoward side effects and might have utility in the management of prostate cancer.

Advances in male contraception

Despite significant advances in contraceptive options for women over the last 50 yr, world population continues to grow rapidly. Scientists and activists alike point to the devastating environmental impacts that population pressures have caused, including global warming from the developed world and hunger and disease in less developed areas. Moreover, almost half of all pregnancies are still unwanted or unplanned. Clearly, there is a need for expanded, reversible, contraceptive options. Multicultural surveys demonstrate the willingness of men to participate in contraception and their female partners to trust them to do so. Notwithstanding their paucity of options, male methods including vasectomy and condoms account for almost one third of contraceptive use in the United States and other countries. Recent international clinical research efforts have demonstrated high efficacy rates (90-95%) for hormonally based male contraceptives. Current barriers to expanded use include limited delivery methods and perceived regulatory obstacles, which stymie introduction to the marketplace. However, advances in oral and injectable androgen delivery are cause for optimism that these hurdles may be overcome. Nonhormonal methods, such as compounds that target sperm motility, are attractive in their theoretical promise of specificity for the reproductive tract. Gene and protein array technologies continue to identify potential targets for this approach. Such nonhormonal agents will likely reach clinical trials in the near future. Great strides have been made in understanding male reproductive physiology; the combined efforts of scientists, clinicians, industry and governmental funding agencies could make an effective, reversible, male contraceptive an option for family planning over the next decade.

Determinants of the rate and extent of spermatogenic suppression during hormonal male contraception: an integrated analysis

CONTEXT

Male hormonal contraceptive methods require effective suppression of sperm output.

OBJECTIVE

The objective of the study was to define the covariables that influence the rate and extent of suppression of spermatogenesis to a level shown in previous World Health Organization-sponsored studies to be sufficient for contraceptive purposes (< or =1 million/ml).

DESIGN

This was an integrated analysis of all published male hormonal contraceptive studies of at least 3 months' treatment duration.

SETTING

Deidentified individual subject data were provided by investigators of 30 studies published between 1990 and 2006.

PARTICIPANTS

A total of 1756 healthy men (by physical, blood, and semen exam) aged 18-51 yr of predominantly Caucasian (two thirds) or Asian (one third) descent were studied. This represents about 85% of all the published data.

INTERVENTION(S)

Men were treated with different preparations of testosterone, with or without various progestins.

MAIN OUTCOME MEASURE

Semen analysis was the main measure.

RESULTS

Progestin coadministration increased both the rate and extent of suppression. Caucasian men suppressed sperm output faster initially but ultimately to a less complete extent than did non-Caucasians. Younger age and lower initial blood testosterone or sperm concentration were also associated with faster suppression, but the independent effect sizes for age and baseline testicular function were relatively small.

CONCLUSION

Male hormonal contraceptives can be practically applied to a wide range of men but require coadministration of an androgen with a second agent (i.e. progestin) for earlier and more complete suppression of sperm output. Whereas considerable progress has been made toward defining clinically effective combinations, further optimization of androgen-progestin treatment regimens is still required.

The effect of 5alpha-reductase inhibition with dutasteride and finasteride on bone mineral density, serum lipoproteins, hemoglobin, prostate specific antigen and sexual function in healthy young men

PURPOSE

Dutasteride and finasteride are 5alpha-reductase inhibitors that dramatically decrease serum levels of dihydrotestosterone. Because androgens affect bone, lipids, hematopoiesis, prostate and sexual function, we determined the impact of 5alpha-reductase inhibitors on these end points.

MATERIALS AND METHODS

We conducted a randomized, double-blinded, placebo controlled trial of 99 men 18 to 55 years old randomly assigned to receive 0.5 mg dutasteride (33), 5 mg finasteride (34) or placebo (32) daily for 1 year. Bone mineral density was measured at baseline, after 1 year of treatment and 6 months after drug discontinuation. In addition, markers of bone turnover, fasting serum lipoprotein concentrations, hemoglobin and prostate specific antigen were measured at baseline, after 26 and 52 weeks of treatment, and again 24 weeks after drug discontinuation. Sexual function was assessed at these points by a validated questionnaire.

RESULTS

Significant suppression of circulating dihydrotestosterone levels with the administration of dutasteride or finasteride did not significantly affect bone mineral density or markers of bone metabolism. Similarly serum lipoproteins and hemoglobin were unaffected. Serum prostate specific antigen and self-assessed sexual function decreased slightly during treatment with both 5alpha-reductase inhibitors but returned to baseline during followup.

CONCLUSIONS

Profound suppression of circulating serum dihydrotestosterone induced by 5alpha-reductase inhibitors during 1 year does not adversely impact bone, serum lipoproteins or hemoglobin, and has a minimal, reversible effect on serum prostate specific antigen and sexual function in normal men. Circulating dihydrotestosterone does not appear to have a clinically significant role in modulating bone mass, hematopoiesis or lipid metabolism in normal men.

Higher testosterone levels are associated with increased high-density lipoprotein cholesterol in men with cardiovascular disease: results from the Massachusetts Male Aging Study

AIM

To study the relationship between circulating androgens (total testosterone [TT], free testosterone [fT] and dihydrotestosterone [DHT]) and high-density lipoprotein cholesterol (HDL-C) in men with and without cardiovascular disease (CVD).

METHODS

Cross-sectional analyses included 1 661 baseline samples from the Massachusetts Male Aging Study (MMAS), a population-based cohort of men ages 40-70 years. Serum hormones were measured by radioimmunoassay and HDL-C was determined following precipitation of the lower density lipoproteins. CVD was determined by self-report. Analyses were performed using multiple linear regression.

RESULTS

TT and HDL-C were positively correlated in the entire sample (r=0.11, P=0.0001). After adjusting for confounders, we found this relationship was mostly limited to the 209 men with CVD. Among men with CVD, TT (P=0.0004), fT (P=0.0172) and DHT (P=0.0128) were all positively correlated with HDL-C, whereas in men without CVD only TT correlated with HDL-C (P=0.0099).

CONCLUSION

Our results suggest that if androgens contribute to CVD in middle-aged men, the effect is not related to a suppressive effect of endogenous T on HDL-C.

Intraprostatic androgens and androgen-regulated gene expression persist after testosterone suppression: therapeutic implications for castration-resistant prostate cancer

Androgen deprivation therapy (ADT) remains the primary treatment for advanced prostate cancer. The efficacy of ADT has not been rigorously evaluated by demonstrating suppression of prostatic androgen activity at the target tissue and molecular level. We determined the efficacy and consistency of medical castration in suppressing prostatic androgen levels and androgen-regulated gene expression. Androgen levels and androgen-regulated gene expression (by microarray profiling, quantitative reverse transcription-PCR, and immunohistochemistry) were measured in prostate samples from a clinical trial of short-term castration (1 month) using the gonadotropin-releasing hormone antagonist, Acyline, versus placebo in healthy men. To assess the effects of long-term ADT, gene expression measurements were evaluated at baseline and after 3, 6, and 9 months of neoadjuvant ADT in prostatectomy samples from men with localized prostate cancer. Medical castration reduced tissue androgens by 75% and reduced the expression of several androgen-regulated genes (NDRG1, FKBP5, and TMPRSS2). However, many androgen-responsive genes, including the androgen receptor (AR) and prostate-specific antigen (PSA), were not suppressed after short-term castration or after 9 months of neoadjuvant ADT. Significant heterogeneity in PSA and AR protein expression was observed in prostate cancer samples at each time point of ADT. Medical castration based on serum testosterone levels cannot be equated with androgen ablation in the prostate microenvironment. Standard androgen deprivation does not consistently suppress androgen-dependent gene expression. Suboptimal suppression of tumoral androgen activity may lead to adaptive cellular changes allowing prostate cancer cell survival in a low androgen environment. Optimal clinical efficacy will require testing of novel approaches targeting complete suppression of systemic and intracrine contributions to the prostatic androgen microenvironment.

Sex steroids and all-cause and cause-specific mortality in men

BACKGROUND

Sex steroid levels are related to metabolic outcomes that could convey higher risk of premature death.

METHODS

We examined whether total or free testosterone, dihydrotestosterone, and sex hormone-binding globulin levels are related to all-cause or cause-specific mortality in men. Data were obtained from the Massachusetts Male Aging Study, a population-based cohort study of 1709 men aged 40 to 70 years. Men were followed up for all-cause and cause-specific mortality.

RESULTS

Complete data were available for 1686 men, with 395 deaths occurring during 15.3 years of follow-up. With age adjustment, dihydrotestosterone and sex hormone-binding globulin levels were associated with ischemic heart disease mortality, and free testosterone level was associated with respiratory mortality. In multivariate-adjusted models, higher free testosterone (P=.02) and lower dihydrotestosterone (P=.04) levels were significantly associated with ischemic heart disease mortality, although the latter association was not robust to differences in model selection. The relative risk of death from ischemic heart disease per 1-SD lower free testosterone level was 0.80 (95% confidence interval, 0.64-0.99). Free testosterone level was significantly associated with respiratory mortality (P=.002), with a multivariate-adjusted relative risk per 1-SD lower free testosterone level of 1.90 (95% confidence interval, 1.24-2.92). Total testosterone level was unrelated to mortality, and sex hormone-binding globulin was not significantly associated with mortality after multivariate adjustment.

CONCLUSIONS

In men, endogenous sex steroid levels seem to have relatively weak associations with mortality. These data provide little support for the hypothesis that endogenous sex steroid levels are associated with risk of premature death but suggest that further investigation of the relationship between sex steroids and mortality from ischemic heart disease and respiratory disease may be warranted.

Intratesticular androgens and spermatogenesis during severe gonadotropin suppression induced by male hormonal contraceptive treatment

Male hormonal contraceptive regimens function by suppressing gonadotropin secretion, resulting in a dramatic decrease in testicular androgen biosynthesis and spermatogenesis. Animal studies suggest that persistent intratesticular (iT)-androgen production has a stimulatory effect on spermatogenesis in the setting of gonadotropin suppression. We hypothesized that men with incompletely suppressed spermatogenesis (>1,000,000 sperm/mL) during male hormonal contraceptive treatment would have higher iT-androgen concentrations than men who achieved severe oligospermia (<or=1,000,000 sperm/mL). Twenty healthy men ages 18-55 years enrolled in a 6-month male contraceptive study of transdermal testosterone (T) gel (100 mg/d) plus depomedroxyprogesterone acetate (300 mg intramuscularly every 12 weeks) with or without the gonadotropin releasing hormone (GnRH) antagonist acyline (300 microg/kg subcutaneously every 2 weeks for 12 weeks) were studied. During the 24th week of treatment, subjects underwent fine needle aspirations of the testes and iT-T and iT-dihydrotestosterone (iT-DHT) were measured in testicular fluid by liquid chromatography-tandem mass spectrometry. All men dramatically suppressed spermatogenesis; 15 of 20 men were severely oligospermic, and 5 of 20 suppressed to 1.5 million-3.2 million sperm per milliliter. In all subjects, mean iT-T and iT-DHT concentrations were 35 +/- 8 and 5.1 +/- 0.8 nmol/L. IT-androgen concentrations did not significantly differ in men who did and did not achieve severe oligospermia (P = .41 for iT-T; P = .18 for iT-DHT). Furthermore, there was no significant correlation between iT-T or iT-DHT and sperm concentration after 24 weeks of treatment. In this study of prolonged gonadotropin suppression induced by male hormonal contraceptive treatment, differences in iT-androgens did not explain differences in spermatogenesis. Additional studies to identify factors involved in persistent spermatogenesis despite gonadotropin suppression are warranted.

The effect of 5alpha-reductase inhibition with dutasteride and finasteride on semen parameters and serum hormones in healthy men

CONTEXT

Dutasteride and finasteride are 5alpha-reductase inhibitors (5ARIs) that dramatically reduce serum levels of dihydrotestosterone (DHT).

OBJECTIVE

Because androgens are essential for fertility, we sought to determine the impact of 5ARI administration on serum testosterone (T), DHT, and spermatogenesis. DESIGN, SETTING, SUBJECTS, AND INTERVENTION: We conducted a randomized, double-blinded, placebo-controlled trial in 99 healthy men randomly assigned to receive dutasteride (D; 0.5 mg) (n = 33), finasteride (F; 5 mg) (n = 34), or placebo (n = 32) once daily for 1 yr.

MAIN OUTCOME MEASURES

Blood and semen samples were collected at baseline and 26 and 52 wk of treatment and 24 wk after treatment and were assessed for T, DHT, and semen parameters.

RESULTS

D and F significantly (P < 0.001) suppressed serum DHT, compared with placebo (D, 94%; F, 73%) and transiently increased serum T. In both treatment groups, total sperm count, compared with baseline, was significantly decreased at 26 wk (D, -28.6%; F, -34.3%) but not at 52 wk (D, -24.9%; F, -16.2%) or the 24-wk follow-up (D, -23.3%; F, -6.2%). At 52 wk, semen volume was decreased (D, -29.7%; F, -14.5%, significantly for D) as was sperm concentration (D, -3.2%; [corrected] F, -7.4%, neither significant). There was a significant reduction of -6 to 12% in sperm motility during treatment with both D and F and at follow-up. Neither treatment had any effect on sperm morphology.

CONCLUSIONS

This study demonstrates that the decrease in DHT induced by 5ARIs is associated with mild decreases in semen parameters that appear reversible after discontinuation.

Serum 17-hydroxyprogesterone strongly correlates with intratesticular testosterone in gonadotropin-suppressed normal men receiving various dosages of human chorionic gonadotropin

OBJECTIVE

To determine if serum concentrations of testosterone precursors would correlate with intratesticular testosterone (ITT) concentration measured directly by testicular aspiration and allow for a less invasive means of inferring ITT.

DESIGN

Controlled clinical study.

SETTING

Healthy volunteers in an academic research environment.

PATIENT(S)

Twenty-nine normal men.

INTERVENTION(S)

We determined ITT concentration by testicular aspiration before and after treatment in men receiving exogenous T to block endogenous gonadotropin production and randomly assigned to one of four doses of hCG (0, 125 IU, 250 IU, or 500 IU every other day) for 3 weeks.

MAIN OUTCOME MEASURE(S)

The association between serum 17-hydroxyprogesterone (17OH-P), androstenedione, and DHEA and ITT.

RESULT(S)

With T administration alone, serum 17OH-P decreased significantly and increased significantly when 500 IU hCG was administered. End-of-treatment ITT strongly correlated with serum 17OH-P. Moreover, serum 17OH-P, but not androstenedione or DHEA, was independently associated with end-of-treatment ITT by multivariate linear regression.

CONCLUSION(S)

Serum 17OH-P is highly correlated with ITT in gonadotropin-suppressed normal men receiving T and stimulated with hCG. Serum 17OH-P is a surrogate biomarker of ITT and may be useful in research and in men receiving gonadotropin therapy for infertility.

Elevated End-of-Treatment Serum INSL3 Is Associated With Failure to Completely Suppress Spermatogenesis in Men Receiving Male Hormonal Contraception

The administration of testosterone plus a progestogen functions as a male contraceptive by inhibiting the release of pituitary gonadotropins. After 3 to 4 months of treatment, most men are azoospermic or severely oligospermic (< or =1 million sperm/mL). However, 10% to 20% of men have persistent sperm production despite profound gonadotropin suppression. Since insulin-like factor 3 (INSL3) has been shown to prevent germ cell apoptosis in mice, we hypothesized that INSL3 might be higher in men with persistent spermatogenesis during treatment with male hormonal contraceptives. In a retrospective analysis, we measured serum INSL3 in 107 men from 3 recent male hormonal contraceptive studies and determined the relationship between suppression of spermatogenesis and serum INSL3. At the end of treatment 63 men (59%) were azoospermic and 44 men (41%) had detectable sperm in their ejaculates. Baseline INSL3 did not predict azoospermia; however, end of treatment serum INSL3 was significantly higher in nonazoospermic men compared with those with azoospermia (median [interquartile range]: 95 [73-127] pg/mL vs 80 [67-101] pg/mL; P = .03). Furthermore, serum INSL3 was positively correlated with sperm concentration (r = .25; P = .009) at the end of treatment and was significantly associated with nonazoospermia by multivariate logistic regression (P = .03). After 6 months of treatment with a hormonal male contraceptive regimen, higher serum INSL3 concentrations were associated with persistent sperm production. INSL3 may play a role in preventing complete suppression of spermatogenesis in some men on hormonal contraceptive regimens. This finding suggests that INSL3 may be a potential target for male contraceptive development.

Acceptability of a combination testosterone gel and depomedroxyprogesterone acetate male contraceptive regimen

BACKGROUND

Testosterone (T) gel, administered transdermally in combination with injections of depomedroxyprogesterone acetate (DMPA) every 3 months, results in effective suppression of spermatogenesis in 90% of men. Men's attitudes regarding the daily self-administration of T-gel and the impact of such a regimen on sexual function, however, are unknown. Therefore, we questioned subjects enrolled in a combination T-gel plus DMPA male contraceptive trial regarding the acceptability of T-gel for male contraception and the impact of the T-gel/DMPA regimen on sexual function and satisfaction during treatment.

STUDY DESIGN

Thirty-eight healthy men, ages 18-55, were treated with T-gel (100 mg daily) + DMPA (300 mg every 3 months) for 24 weeks. Sexual function was assessed using a validated questionnaire at baseline, after 12 and 24 weeks of treatment and 12 weeks into recovery. The overall acceptability of the method and attitudes regarding the daily self-administration of T-gel were assessed by a questionnaire 12 weeks into recovery.

RESULTS

Fifty percent of subjects were either satisfied or very satisfied with the T-gel-based contraceptive regimen, and 45% indicated they would use the regimen if it were commercially available. The T-gel was found to be easy to use by 76% of men, but a third of subjects felt that T-gel administration interfered with their daily routine. Sexual function was largely preserved during treatment; however, slight decreases in sexual function were noted during recovery.

CONCLUSIONS

The experimental male hormonal contraceptive regimen of T-gel + DMPA is acceptable to approximately one half of study volunteers, most of whom would use the method if it were commercially available. Given its appeal to a significant proportion of men, additional studies using T-gel and DMPA for male contraception are warranted.

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.