Sperm function in Indonesian men treated with testosterone enanthate

This study was undertaken to assess the fertilizing capacity (sperm function) of residual spermatozoa produced by groups of men (n = 7) rendered oligozoospermic by treatment with weekly intramuscular injection of 50 or 100 mg testosterone enanthate (TE). The treatment was continued for 6 months and the effects compared with a control group (n = 6) in which men received weekly intramuscular injections of sesame oil (1 ml). Sperm function was assessed by tests of membrane integrity (supravital stain and hypoosmotic swelling [HOS] test) and sperm penetration (artificial cervical capillary tube test). The quality of sperm movement was also assessed. These parameters of sperm function were all reduced consistently in a dose-dependent manner with maximal suppression occurring between weeks 15 and 25 of treatment, and full recovery to baseline levels by 12 months after cessation of treatment. The decrease in sperm function was correlated with the degree of suppression of sperm output with the proportion of morphologically normal spermatozoa and the degree of suppression of gonadotrophin levels. The weekly dose of 50 mg TE induced severe oligozoospermia (concentration < 5 million/ml) in four of seven men, whereas 100 mg TE induced azoospermia in all seven men by week 20. It is concluded that, unlike published observations on men of European background, the administration of TE at 100 mg per week may achieve adequate contraceptive efficacy in Indonesian men.

Single-dose administration of the gonadotropin-releasing hormone antagonist, Nal-Lys (antide) to healthy men

OBJECTIVE

To evaluate the ability the Nal-Lys GnRH antagonist ([N-Ac-Nal (2)1, 4ClDPhe2, D3Pal3, Lys (Nic)5, D-Lys(Nic)6, Lys (iPr)8, D-Ala10] to suppress gonadotropins and T in humans and to assess its duration of action and its local effects.

DESIGN

Placebo-controlled clinical study.

SETTING

A university community.

SUBJECTS

Seven normal male volunteers.

INTERVENTIONS

We administered single injections of Nal-Lys (0, 10, 25, and 50 micrograms/kg body weight). Blood samples were collected before and at frequent time intervals after injection.

RESULTS

Nal-Lys caused only minor local effects. At the higher doses (25 and 50 micrograms/kg), serum LH and T levels were suppressed to 50% to 70% of baseline; serum FSH levels were suppressed to 70% to 80% of baseline, and levels of all three hormones returned to basal values within 24 hours after injection.

CONCLUSIONS

In humans, Nal-Lys has similar potency and duration of action to other antagonists and produces fewer local side effects. However, the utility of Nal-Lys is limited by formulation difficulties; current efforts are directed at improving the formulation in order to explore the potential clinical uses of this peptide.

Comparison between testosterone enanthate-induced azoospermia and oligozoospermia in a male contraceptive study. I: Plasma luteinizing hormone, follicle stimulating hormone, testosterone, estradiol, and inhibin concentrations

Sex-steroid based male contraceptive regimes induce azoospermia in only 40-70% of Caucasian men. The reason(s) why the remainder maintains a low level of spermatogenesis (oligozoospermia) despite gonadotrophin suppression is unclear. In order to improve our understanding of this phenomenon, we examined the changes in sperm density and plasma LH, FSH, testosterone (T), oestradiol (E2), and inhibin (IN) in 28 normal men who received 200 mg testosterone enanthate (TE) im weekly during a male contraceptive efficacy trial. Gonadotrophins were measured by an ultrasensitive time-resolved immunofluorometric assay (DELFIA) with a sensitivity of 0.04 U/L, to determine the adequacy of suppression. Seventeen of the 28 men achieved azoospermia; the other 11 remained oligozoospermic (sperm density 3.3-4.7 x 10(6)/mL) after 6 months of TE exposure. Azoospermic subjects displayed a more rapid decline in sperm density, a significant difference being apparent by 5 weeks after starting TE. During TE treatment, both LH and FSH were consistently suppressed to below the limits of detection, whereas there was a 2.5-fold rise in T and E2 with a similar decrease in IN. There were no consistent differences in any of these hormone concentrations between the azoospermic and oligozoospermic groups. Recovery of sperm density to baseline levels or above 20 x 10(6)/mL was significantly slower in the azoospermic group. During the recovery phase, the azoospermic men exhibited significantly higher LH and FSH levels compared to baseline and to the oligozoospermic subjects even though no differences in circulating T, E2, or IN were observed. We conclude that incomplete gonadotrophin suppression or differences in sex steroid or inhibin levels are unlikely to be responsible for the maintenance of minor degrees of spermatogenesis in some men during TE administration. The rebound rise in gonadotrophins in azoospermic but not oligozoospermic responders during recovery may reflect a more profound degree of spermatogenic suppression in the former group.

7 alpha-methyl-nortestosterone (MENT): the optimal androgen for male contraception

Many methods of contraception involve the use of drugs that affect the secretion of hormones essential for reproduction. Oestrogens and progestins have been used for contraction in women as inhibitors of gonadotrophin secretion and ovulation. Similarly, androgens must be used in methods of fertility control for men that block gonadotrophin secretion. Androgen supplementation currently involves large, frequent doses of testosterone esters that are associated with wide fluctuations of plasma testosterone levels. Hence, there is a need for an androgen preparation that provides appropriate, continuous replacement doses over long periods. To achieve this goal, 7 alpha-methyl-19-nortestosterone (MENT), a synthetic androgen that is considerably more potent than testosterone, is suitable. As a consequence, it is feasible to administer this androgen as a substitute for testosterone for 1 year by subdermal implants. Another important feature of MENT is that it does not undergo 5 alpha- reduction in prostate as does testosterone. As a consequence, a dose of MENT sufficient to maintain normal muscle mass and gonadotrophin secretion will not hyperstimulate the prostate because its action in this organ is not amplified as is that of testosterone. Thus, MENT can be administered to men with the assurance that it will be less prone to cause diseases of the prostate than testosterone.

CONCLUSIONS

(i) MENT is the first androgen that has a health benefit compared to testosterone; (ii) MENT will be promoted as one component of a two-implant system for male contraception, the other component being an implant that will release an LHRH analogue; (iii) MENT has potential uses in patients with a variety of disorders, including hypogonadism, prostatic hyperplasia and muscle wasting.

Development of copper male contraceptive. Contribution of India

In this review article the author discusses the possibility of making a male contraceptive with the inclusion of copper. The contributions made by different groups of workers in India towards this, are critically analysed. Aspermatogenic status of copper is recognised. The toxicity of copper on tissue is a great concern for continuation of this programme. Recently a hypothesis for slow delivery system of copper for functioning as aspermatogenic and spermatostatic was mooted. The veracity of the proposal is yet to be seen.

Factors that determine prevalence of use of contraceptive methods for men

Globally, men have not shared equally with women the responsibility for fertility regulation. While family planning efforts have been directed almost exclusively toward women, the lack of male involvement may also reflect the limited options available to men. Current methods for men are either coitus-dependent, such as the condom or withdrawal, or permanent, such as vasectomy. The 20-year history of social science research on male contraceptive methods is examined here in terms of the human and method factors related to the acceptability of hypothetical methods and the prevalence of use of existing methods. New male methods, particularly if reversible, may alter men's willingness to accept or share responsibility for the control of fertility. Research opportunities in the areas of gender, decision-making, communication, health education, and service delivery will be enhanced when methods for women and men are comparable.

Prostate-specific antigen and prostate gland size in men receiving exogenous testosterone for male contraception

Steroid regimens containing androgens are being evaluated currently as hormonal contraceptives for men. The possible non-reproductive effects of such treatment were assessed during an efficacy trial using a prototype regime of 200 mg testosterone enanthate i.m. weekly. Prostatic function and size were monitored by regular rectal examination, blood levels of prostate-specific androgen (PSA) were measured in 30 men and prostatic size was measured by trans-rectal ultrasound imaging in a representative subgroup of five subjects for 12 months and for a further 6 months after discontinuation. Despite the sustained rise in serum levels of testosterone, oestradiol and dihydrotestosterone during treatment, there was no detectable increase in prostatic size on rectal examination or any significant change in blood concentrations of PSA. A small but significant increase (14.3 +/- 2.0%) in maximal prostate transverse area was observed in four men while the remaining one showed no change. Our preliminary data demonstrate the feasibility and importance of monitoring prostatic function in the development of androgen-containing male hormonal contraceptives.

Male fertility regulation: the challenges for the year 2000

The search for new, safe, effective and reversible contraceptive methods for men is being pursued by several agencies. The most likely developments before the year 2000 would appear to be: the introduction of more easily reversed procedures of vas occlusion; hormonal means of sperm suppression based on infrequent injections of androgens either alone or combined with other gonadotrophin-suppressing agents. Methods based on new drugs or vaccines are unlikely to be developed by the end of the decade. Research is needed to understand the basis of the differences in efficacy of contraceptive steroids in men of different ethnic origin. Equally there is a need to monitor the safety and acceptability of hormonal methods for men. New targets for drug intervention should be pursued through support of basic science, taking advantage of modern cellular and molecular biological techniques. Finally, the subject of Andrology needs to be strengthened throughout the world so that scientists in developing countries can participate fully in this work.

GnRH analogues for contraception

The production of chemical analogues of GnRH permits direct suppression of the pituitary-gonadal axis at the level of the gonadotroph. Continuous administration of GnRH agonists desensitizes the gonadotroph and ovulation is uniformly prevented, forming the practical basis for use in contraception. However, long-term treatment is constrained by variable effects on oestrogen secretion, which cause irregular bleeding patterns on the one hand and risks of hypo-oestrogenism on the other. Their use as a post-partum contraceptive has attractions because any analogue in milk should be without biological activity in the infant. GnRH antagonists have the advantage of immediate inhibitory action. They have potential application in circumstances in which agonists have been employed and, in addition, can interrupt any stage of the menstrual cycle. Clinical trials to utilise their potential antifertility action have not been performed. Use of GnRH analogues for contraception in women may require combination with low dose oestrogen and progestin and it has been proposed that such development may yield important benefits in health. When combined with testosterone, GnRH antagonists may form the basis for a male contraceptive.

Anti-LHRH and anti-pituitary gonadotropin vaccines: their development and clinical applications

Active immunization against hormones involved in the regulation of reproduction is a promising approach to immunocontraception. The hypothalamic peptide, LHRH, controls the synthesis and release of the pituitary gonadotropins, LH and FSH, which regulate gonadal steroidogenesis, sperm production, follicular development and ovulation. Immunizing female primates against LHRH or LH induces infertility, but also disrupts the menstrual cycle. Immunization against the beta subunit of the placental hormone, chorionic gonadotropin (hCG), or its fragment prevents pregnancy without interfering with menstrual cycles or ovulation. hCG vaccines have reached the stage of clinical trials. FSH and LHRH have been tested for immunocontraception in male primates. While active as well as passive immunization against FSH reduced spermatogenesis severely, azoospermia could not be achieved consistently. Immunization against LHRH effectively suppressed spermatogenesis in rats and rabbits. Normal sexual behaviour was maintained by concomitant androgen administration. Fertility was restored when antibody titres declined and no adverse effects were observed. A number of LHRH vaccine preparations are being tested in men in several countries, including the United States. Since the LHRH vaccine reduces serum testosterone levels the first clinical studies involve men with prostate cancer. These trials will be followed by immunization of normal men if the antibody response is sufficient and no adverse effects are observed.

FDA requirements for nonclinical testing of contraceptive steroids

Written guidelines for the preclinical testing of contraceptive steroids have not been revised since 1968 despite the fact that many important changes have been implemented by the FDA's Division of Metabolism and Endocrine Drug Products. This paper describes the new preclinical testing requirements and the rationale for their implementation.

Contraceptive efficacy of polyester-induced azoospermia in normal men

The contraceptive effect of a polyester sling applied to the scrotum was studied in 14 men. The suspensor was worn for 12 months. Follow-up investigations comprised periodic check of semen character, testicular size, rectal-testicular temperature difference, serum reproductive hormones and testicular biopsy. The electrostatic potentials generated by friction between the polyester suspensor and the scrotal skin were determined. Female partners used contraceptives until the men became azoospermic. After 12 months, the suspensor was abandoned and the aforementioned investigations were performed again. In the suspensor-wearing period, all men became azoospermic after a mean of 139.6 +/- 20.8 sd days, with decrease in both testicular volume (P less than 0.05) and rectal-testicular temperature difference (P less than 0.001). Serum reproductive hormones showed no significant change (P greater than 0.05). Seminiferous tubules revealed degenerative changes. No pregnancy occurred during this period. The polyester suspensor generated electrostatic potentials (mean 366.4 +/- 30.5 sd volt/cm2 by day and 158.3 +/- 13.6 sd volt/cm2 by night). In the suspensor-release period, the sperm concentration returned to the pre-test level in a mean period of 156.6 +/- 14.8 sd days. Likewise, the testicular volume and rectal-testicular temperature difference were normalized. The 5 couples, who had planned to become pregnant, conceived. The azoospermic effect of the polyester sling seems to be due to two mechanisms: 1) the creation of an electrostatic field across the intrascrotal structures, and 2) disordered thermoregulation. To conclude, fertile men can be rendered azoospermic by wearing the polyester sling. It is a safe, reversible, acceptable and inexpensive method of contraception in men.

Developments in the control of testicular function

Clinicians and clinical investigators have developed improved means for controlling testicular function in men. New and refined approaches for stimulation and inhibition of the hypothalamic-pituitary-testicular axis are now available. This chapter reviewed the most successful ways to inhibit the reproductive axis in men and its current application to the treatment of precocious puberty, metastatic prostate cancer, benign prostate hyperplasia and as prospective male contraceptives. Safe, effective and reversible medical approaches to male contraception are now approaching reality. Azoospermia and severe oligozoo/azoospermia can now be accomplished in the majority of men with combined GnRH antagonists and replacement doses of testosterone. Androgens and androgen-progestogen concentrations will induce azoospermia in over 90% of Asian men and azoospermia or severe oligospermia in Caucasian ethnic groups. Field trials are ongoing to determine whether testosterone administration will be more effective than condoms as contraceptives. True precocious puberty can now be managed more effectively than in the past by suppression of gonadotropin secretion with GnRH analogues. Precocious puberty due to other causes can be treated more effectively with inhibitors of steroidogenesis and blockers of androgen action. Metastatic prostate cancer, previously treatable with either castration or oestrogens, is now amenable to suppression of androgen secretion. GnRH analogues are given either alone or combined with blockers of androgen action. While significant palliative effects are observed with endocrine ablative therapy in most men with Stage C or D prostate cancer, modest increases in duration of survival may be seen. Benign prostate hyperplasia was previously approachable only with surgical intervention. Recent data have suggested that medical treatment with 5 alpha-reductase inhibitors and/or selective alpha-adrenergic blockers may offer non-surgical alternatives in some patients. More data are needed to determine the role of medical management of this common disorder.