Suppression of spermatogenesis in man induced by Nal-Glu gonadotropin releasing hormone antagonist and testosterone enanthate (TE) is maintained by TE alone

Use of Exogenous Testosterone for the Treatment of Male Factor Infertility: A Survey of Nigerian Doctors

Background

Though exogenous testosterone is known for its contraceptive effects in men, it is sometimes prescribed by medical practitioners for the treatment of male factor infertility in the mistaken belief that exogenous testosterone improves sperm count. The aim of this study was to evaluate the scope of testosterone use in the treatment of male factor infertility by medical practitioners in Lagos, Nigeria.

Methods

A survey using a structured questionnaire was carried out amongst doctors attending a regular Continuing Medical Education (CME) programme in Lagos, Nigeria.

Results

There were 225 respondents. Most of the respondents (69.8%, n = 157) indicated that exogenous testosterone increases sperm count. Only 22 respondents (9.8%) indicated (correctly) that exogenous testosterone decreases sperm count. Seventy-seven respondents (34.2%) had prescribed some form of exogenous testosterone in the treatment of male factor infertility. The vast majority of respondents who had prescribed testosterone (81.8%, n = 63) thought exogenous testosterone increases sperm count. There was no statistically significant difference in the pattern of prescription across the respondents' specialty (p = 0.859) or practice type (p = 0.747).

Conclusion

The misuse of exogenous testosterone for the treatment of male infertility was common amongst the respondents, with most of them wrongly believing that exogenous testosterone increases sperm count.

Male Hormonal Contraception: Where Are We Now?

Hormonal male contraception clinical trials began in the 1970s. The method is based on the use of exogenous testosterone alone or in combination with a progestin to suppress the endogenous production of testosterone and spermatogenesis. Studies using testosterone alone showed that the method was very effective with few adverse effects. Addition of a progestin increases the rate and extent of suppression of spermatogenesis. Common adverse effects include acne, injection site pain, mood change including depression, and changes in libido that are usually mild and rarely lead to discontinuation. Current development includes long-acting injectables and transdermal gels and novel androgens that may have both androgenic and progestational activities. Surveys showed that over 50 % of men will accept a new male method and female partners will trust their partner to take oral “male pills.” Partnership between government, nongovernment agencies, academia, and industry may generate adequate interest and collaboration to develop and market the first male hormonal contraception.

Male contraception

Clear evidence shows that many men and women would welcome new male methods of contraception, but none have become available. The hormonal approach is based on suppression of gonadotropins and thus of testicular function and spermatogenesis, and has been investigated for several decades. This approach can achieve sufficient suppression of spermatogenesis for effective contraception in most men, but not all; the basis for these men responding insufficiently is unclear. Alternatively, the non-hormonal approach is based on identifying specific processes in sperm development, maturation and function. A range of targets has been identified in animal models, and targeted effectively. This approach, however, remains in the pre-clinical domain at present. There are, therefore, grounds for considering that safe, effective and reversible methods of contraception for men can be developed.

Endocrine control of spermatogenesis: Role of FSH and LH/ testosterone

Evaluation of testicular functions (production of sperm and androgens) is an important aspect of preclinical safety assessment and testicular toxicity is comparatively far more common than ovarian toxicity. This chapter focuses (1) on the histological sequelae of disturbed reproductive endocrinology in rat, dog and nonhuman primates and (2) provides a review of our current understanding of the roles of gonadotropins and androgens. The response of the rodent testis to endocrine disturbances is clearly different from that of dog and primates with different germ cell types and spermatogenic stages being affected initially and also that the end-stage spermatogenic involution is more pronounced in dog and primates compared to rodents. Luteinizing hormone (LH)/testosterone and follicle-stimulating hormone (FSH) are the pivotal endocrine factors controlling testicular functions. The relative importance of either hormone is somewhat different between rodents and primates. Generally, however, both LH/testosterone and FSH are necessary for quantitatively normal spermatogenesis, at least in non-seasonal species.

Male contraception

Contraception is an accepted route for the control of population explosion in the world. Traditionally hormonal contraceptive methods have focused on women. Male contraception by means of hormonal and non hormonal methods is an attractive alternative. Hormonal methods of contraception using testosterone have shown good results. Non hormonal reversible methods of male contraception like reversible inhibition of sperm under guidanceare very promising. In this article we have reviewed the current available options for male contraception.

Hormonal approaches to male contraception

PURPOSE OF REVIEW

Condoms and vasectomy are male-controlled family planning methods but suffer from limitations in compliance (condoms) and limited reversibility (vasectomy); thus many couples desire other options. Hormonal male contraceptive methods have undergone extensive clinical trials in healthy men and shown to be efficacious, reversible and appear to be well tolerated.

RECENT FINDINGS

The success rate of male hormonal contraception using injectable testosterone alone is high and comparable to methods for women. Addition of progestins to androgens improved the rate of suppression of spermatogenesis. Supported by government or nongovernment organizations, current studies aim to find the best combination of testosterone and progestins for effective spermatogenesis suppression and to explore other delivery methods for these hormones. Translation of these advances to widespread use in the developed world will need the manufacturing and marketing skills of the pharmaceutical industry. Availability of male contraceptives to the developing world may require commitments of governmental and nongovernmental agencies. In a time when imbalance of basic resources and population needs are obvious, this may prove to be a very wise investment.

SUMMARY

Male hormonal contraception is efficacious, reversible and well tolerated for the target population of younger men in stable relationships. Suppression of spermatogenesis is achieved with a combination of an androgen and a progestin. Partnership with industry will accelerate the marketing of a male hormonal contraceptive. Research is ongoing on selective androgen and progesterone receptor modulators that suppress spermatogenesis, minimize potential adverse events while retaining the androgenic and gonadotropin suppressive actions.

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.

Men with acquired hypogonadotropic hypogonadism treated with testosterone may be fertile

Men with acquired hypogonadotropic hypogonadism treated with testosterone are generally assumed to be infertile. The finding of two such patients with unexpected fertility and normal sperm counts prompted an evaluation of spermatogenesis in additional men with this condition. Case records were initially searched and one similar case with fertility was found. Subsequently, 12 consecutive men with acquired hypogonadotropic hypogonadism were evaluated for gonadal function and sperm production while receiving testosterone. In five of the cases with proven spermatogenesis, exon 10 of the FSH receptor was sequenced to look for activating mutations. The original three cases and four of the subsequent 12 men had sperm concentrations > or = 15 million/ml. Two additional men had concentrations of 1 million/ml and six were azoospermic. Residual LH and FSH levels were slightly higher in those with maintained spermatogenesis prior to testosterone replacement. No activating mutations were found in exon 10 of the FSH receptor in the five cases studied. We conclude that men with acquired hypogonadotropic hypogonadism being treated with testosterone should not be assumed to be sterile, as we have found that more than half have been shown to have persistent spermatogenesis with more than one-third having sperm concentrations > or = 15 million/ml. This may be related to fact that gonadotropin levels in such patients are present, albeit low. Semen analyses in such men should be routinely carried out so that they can be appropriately counseled regarding potential fertility.