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At least 19 recordsLinked to original sources
PubMed1978

[Problems of male contraception. 2. Male hormonal contraception, post-testicular points of attack, immunization and enzyme inhibition].

In principle control of male fertility is possible by mechanical, surgical and pharmacological methods. However, up to now only the following mechanical and surgical procedures are practicable: coitus interruptus, coitus condomatus and vasectomy. Since the safety of the latter is comparable to the pill, vasectomy is a major alternative to the contraceptive methods used by the female partner. Practical aspects of vasectomy and possible complications are reviewed. Finally, pharmacological approaches and problems involved in the control of male fertility are discussed with special reference to antispermatogenic substances, steroid hormones, immunization and enzyme inhibitors. The concept of antienzymatic contraception is based on the inhibition of penetration of enzymes (acrosin) localized within the acrosomal cap. Unfortunately, penetration of most of the acrosin inhibitors into the acrosome to inactivate acrosin is prevented by the high selectivity of the acrosomal membranes. Thus, pharmacological control of male fertility is still far from being practicable.

Acrosin↗
PubMed1988

Is high dosage testosterone an effective male contraceptive agent?

In male contraceptive trials, approximately half of normal men become azoospermic on high dosages of testosterone enanthate (TE), whereas the other half of men become severely oligozoospermic. To determine whether sperm function is reduced in men with severe oligozoospermia induced by TE, we studied sperm function in six normal men whose sperm counts were reduced to less than or equal to 5 X 10(6)/ml but not to azoospermia by high-dosage TE administration for 5 to 6 months and five normal men who received placebo (sesame oil) injections for the same period of time. Seminal fluid analysis and sperm function (as assessed by zona pellucida-free hamster ova penetration test, HOPT) were performed during a pretreatment period and after at least 3 months of TE or placebo treatment. HOPT was severely reduced in all six men, whose sperm counts were suppressed to severe oligozoospermia during TE (0.8 +/- 0.8% compared to 37 +/- 14% during the pretreatment period, P less than 0.05). Five men failed to penetrate any hamster ova, while the remaining man penetrated only 5% of ova during TE treatment. There were no significant changes in other seminal fluid measurements during high-dosage TE. The five men who received placebo injections did not demonstrate any significant changes in HOPT or seminal fluid analysis during the treatment period. In summary, we found that the fertilizing capacity of sperm is markedly diminished when sperm production is severely reduced by high-dosage TE administration. These findings suggest that male contraception may be achievable by reduction of spermatogenesis to severe oligozoospermia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1977

Ultrasound as a new method of male contraception.

Twenty male cats were treated once or twice with 1 watt/sq cm of ultrasound for 10 minutes. Each of 24 male dogs received one to three treatments with 1 watt/sq cm for 10 minutes. Another six dogs were treated with 2 watts/sq cm for 15 minutes. Four Cebus apella monkeys were treated with the same dosage as that used for the cats and dogs. A dosage of 1 watt/sq cm for 10 minutes was also applied to four human patients without the use of anesthetics, and no pain or side effects were noted. In all treated animals as well as in human patients the results indicate that ultrasound significantly suppresses spermatogenesis according to the dosage and frequency of treatment, without any effect on Leydig cells or blood testosterone levels.

Animals↗
PubMed1990

Pyrimethamine: an approach to the development of a male contraceptive.

With the human population of the world currently more than 5.2 billion and growing at an explosive rate, the need for additional forms of readily available contraception appears paramount. To date, contraception techniques in the male have been very limited. The present study demonstrates the ability of pyrimethamine (PYR) to cause spermatogenic arrest and male infertility in mice in a dose-dependent manner. Furthermore, upon cessation of drug administration all animals returned to normal fertility status. It is also suggested that the action of PYR is due to its antifolate action. Thus, PYR represents another approach toward development of a male contraceptive.

Animals↗
PubMed1992

Passive immunization against prostatic 'inhibin' peptide as a male contraceptive.

Passive immunization of adult male hamsters for 12 weeks against peptide (As-PIP), a sperm coating antigen, resulted in selective elevation of the blood levels of FSH, impairment of spermatogenesis, and complete infertility when males were mated with normal cycling females. Passive immunization of male marmosets with As-PIP for 8 weeks was also effective and was reversible, without causing any obvious change in mating behaviour. These preliminary studies in hamsters and marmosets indicate that antibodies to a prostatic 'inhibin' peptide represent a promising new approach to male contraception.

Animals↗
PubMed1992

Depot gonadotropin-releasing hormone agonist blunts the androgen-induced suppression of spermatogenesis in a clinical trial of male contraception.

Thus far, when tested as male contraceptives, GnRH agonists in combination with androgens were not very effective in producing azoospermia. Since in previous studies androgens were always given simultaneously with the GnRH agonist or later, we tested whether GnRH agonist administration after an initial androgen suppression phase might yield better results. After a control period, 3 groups of young healthy men (n = 8/group) received an initial loading dose of 400 mg 19-nortestosterone hexyloxyphenylpropionate (19NT-HPP), followed by 200 mg of the ester every 3 weeks for 24 weeks. One week after the first 19NT-HPP injection, 2 groups were given a single sc implant injection of 3.3 or 6.6 mg of the GnRH agonist buserelin, respectively, whereas a placebo implant was given to the third group. In the group receiving only 19NT-HPP, serum LH and FSH were markedly suppressed and remained low during the treatment phase. In the 16 volunteers receiving the buserelin implant LH and FSH were also suppressed on day 7, followed by a marked increase in the gonadotropins up to 2 weeks after buserelin implant injection. While LH was consistently suppressed for the remaining treatment phase, FSH returned to almost normal values in weeks 9-15. In contrast to the group treated with 19NT-HPP alone, in which sperm concentrations were reduced to oligozoospermia after only 3 weeks of treatment, the first suppressive effect in the 19NT-HPP/buserelin-treated groups was not seen before week 9. After 30 weeks, when the maximal suppression of spermatogenesis was seen, 4 of 8 volunteers in the group treated with 19NT-HPP alone were azoospermic, and the remaining 4 volunteers were oligozoospermic. In the groups treated with 19NT-HPP/buserelin, no more than 4 of 16 volunteers were azoospermic, and no more than 8 of 16 volunteers were oligozoospermic at any time point. It is concluded that GnRH agonist depot preparations have a blunting effect on the suppression of pituitary and testicular function caused by androgens in men participating in contraceptive trials.

Adult↗
PubMed1979

Pregnancies associated with sperm concentrations below 10 million/ml in clinical studies of a potential male contraceptive method, monthly depot medroxyprogesterone acetate and testosterone esters.

A potential male contraceptive approach was evaluated in clinical trials involving monthly injections of depot medroxyprogesterone acetate and either subdermal implants of testosterone propionate or monthly injections of testosterone enanthate. Pregnancies occurred in partners of 9 men with recent sperm counts of 10 million/ml or below. In 5 of the 9 instances, the sperm counts were less than 1 million/ml. It appears that male contraceptive methods involving spermatogenic suppression may require attainment and maintenance of azoospermia. The pregnancy rate cannot be calculated, because the extent of other contraceptive use is uncertain. There were no spontaneous abortions. 6 pregnancies were carried to term, and all progeny were normal, based on physical examination at birth or 3 months after birth.

Contraceptive Agents, Male↗
PubMed1986

[Male contraception].

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Contraceptive Agents, Male↗
PubMed1987

[Male contraception].

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Contraceptive Agents, Male↗
PubMed1988

Prazosin, an adrenergic blocking agent inadequate as male contraceptive pill.

The purpose of this study was to investigate the efficacy and the acceptability of Prazosin as a male contraceptive pill. Acceptable antifertility drugs for men are proving difficult to produce, and the possibility of using pharmacological agents to block selectively or to inhibit normal sperm transport through the male genital tract is an interesting approach. Prazosin administered in doses up to 10 mg/day did not cause azoospermia following ejaculation. In conclusion, we have not been able to confirm either the efficacy or the acceptability of the alpha 1-adrenoceptor antagonist Prazosin as a male contraceptive drug. Homonnai et al. confirmed the fact that phenoxybenzamine blocks ejaculation, but it should be noted that although both drugs are alpha 1-adrenoceptor blocking agents, they are not chemically identical.

Adrenergic alpha-Antagonists↗
PubMed1990

Chronic toxicity of styrene maleic anhydride, a male contraceptive, in rhesus monkeys (Macaca mulatta).

A newly developed male contraceptive, styrene maleic anhydride (SMA), was injected in the vas deferens of male rhesus monkeys for safety evaluation at the dose of 100 mg (contraceptive dose, CD), 250 mg (CD x 2.5) and 500 mg (CD x 5.0), and the monkeys were kept under observation for one year. The observed behavioural, haematological, biochemical and histopathological parameters in treated monkeys were comparable to controls. The results suggest the polymer SMA to be safe up to 5 times CD in monkeys.

Adrenal Glands↗
PubMed1985

Clastogenicity of a male contraceptive, gossypol, in mammalian cell cultures with and without the metabolic activation by S9 mix.

The clastogenicity of a potential male contraceptive, gossypol, was examined in cultured Chinese hamster cells with and without the presence of a metabolic activation system (rat liver S9 mix). Gossypol at concentrations of 1, 5, and 10 micrograms/ml did not induce chromosome breakage either in the presence or absence of the S9 mix. The ability of this compound to induce chromosome breakage and polyploidy was further examined in human lymphocyte cultures. Neither increased frequencies of chromosome breakage nor polyploidy was found in lymphocyte cultures from two healthy donors. The present study indicates that gossypol does not cause genetic damage at the chromosomal level. This is consistent with previously reported findings that it does not produce mutations in the Ames test. Gossypol has been under clinical trial in China for years and shown to be effective in 99.9% of over 10,000 men tested with no or mild side effects. If this compound can be further proven to be "safe" and approved for world-wide use as a male contraceptive, it would be for the benefit of all mankind.

Animals↗
PubMed1989

Combination of 19-nortestosterone-hexyloxyphenylpropionate (Anadur) and depot-medroxyprogesterone-acetate (Clinovir) for male contraception.

Because monotherapy with 19-nortestosterone hexyloxyphenylpropionate (Anadur, Pharmacia Arzneimittel, Ratingen, Federal Republic of Germany) suggested improved results for male contraception compared with available testosterone esters, it was tested for induction of complete azoospermia when combined with depot-medroxyprogesterone acetate (DMPA, Clinovir, Upjohn GmbH, Heppenheim, Federal Republic of Germany). Twelve men were treated for 7 weeks with weekly intramuscular (IM) injections of 200 mg Anadur followed by 3-weekly IM injections of Anadur up to week 15. Clinovir (250 mg) IM was administered at the start of treatment and during weeks 6 and 12. Anadur and Clinovir suppressed serum gonadotropins. Although serum testosterone declined steeply, in general, libido and potency were not impaired. Sperm concentrations were reduced significantly after 3 weeks of treatment. Lowest sperm counts were seen during week 8 of follow-up, when only 2 volunteers showed measurable sperm counts of 2.1 and 3.0 X 10(6)/ml, with a declining tendency. After 43 weeks, sperm concentrations were still below pretreatment range in 2 men, but later returned to pretreatment values. Computerized sperm motion analysis revealed that motility parameters in the residual sperm were reduced. In vitro analysis excluded a direct effect of medroxyprogesterone acetate in seminal plasma on sperm motion. The data indicate that the combination of Anadur with Clinovir increases the rate of azoospermia in normal volunteers seen under Anadur monotherapy, although the goal of azoospermia in all participants was not quite achieved.

Anabolic Agents↗