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[Male hormonal contraception]. VNITRNI LEKARSTVI 2006; 52:1077-84. [PMID: 17165528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Human reproduction is a complex phenomenon remaining at the center of interest of many medical and extra-medical disciplines and the search for new contraceptive methods is an important part of research effort. The development of effective forms of male hormonal contraception (MHC) is one of the priorities of the World Health Organization (WHO Task Force on Methods of Regulation of Male Fertility). The principle of MHC consists in the suppression of spermatogenesis while preserving all other functional aspects of the male glands (especially the sexual functions, bone metabolism and lean muscle mass). It is possible to stop spermatogenesis by blocking gonadotrophin (FSH and LH) secretion by testosterone administration (isolated or in combination with other hormones). The currently existing variants of MHC are based on testosterone application (which has in the same time the role of substitutive treatment--the so-called androgen "add-back") either in monotherapy (oral, intramuscular, transdermal and subcutaneous form) or in combination with various progestins (levonorgestrel, norethisterone, desogestrel, eronogestrel, medroxyprogesterone), antiandrogens or GnRH analogues. The most promising, at present, seem to be the methods which use a combination of depot testosterone preparations with long-acting progestins. To what extent will the role of MHC be important in the future--this can only be judged after establishing their effectiveness, full reversibility, safe application, acceptability, and financial accessibility in clinical practice.
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Abstract
There are a number of situations in which it is desirable to suppress part or all of the reproductive endocrine system in a horse, notably the competing animal whose tractability during training, or performance during competition, is compromised by the expression of sexual or aggressive behavior. The current therapeutic approaches to reproductive endocrine suppression include gonadectomy and progestagen administration, where the former carries surgical risks and entails irreversible loss of breeding potential, and effective progestagen therapy requires frequent administration for extended periods and is banned in some competing animals as potentially anabolic. In this context, preventing the action of gonadotrophin releasing hormone (GnRH) by blocking its pituitary receptors is an attractive alternative for reversibly rendering mares anestrus or depressing testosterone secretion or spermatogenesis in stallions. This paper reviews the data on effects, efficacy, reversibility, and side effects of GnRH vaccines, antagonists, and agonists for suppressing reproductive activity in horses, within the context of their potential place in the pharmacological armoury of the veterinary clinician.
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3
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The future of male birth control. PLANNED PARENTHOOD REVIEW 2002; 6:11-2. [PMID: 12340896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
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4
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I've heard that scientists are looking at testosterone injections as a form of male contraception. How does adding testosterone make a man infertile? HEALTH NEWS (WALTHAM, MASS.) 2000; 6:10. [PMID: 10997117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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5
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Experimental male methods inhibit sperm. NETWORK (RESEARCH TRIANGLE PARK, N.C.) 1998; 18:16-9, 31. [PMID: 12293529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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6
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Progress in research into new methods of fertility regulation for men. PROGRESS IN HUMAN REPRODUCTION RESEARCH 1995:2. [PMID: 12289975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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7
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GnRH immunization and male infertility: immunocontraception potential. ADVANCES IN CONTRACEPTIVE DELIVERY SYSTEMS : CDS 1994; 10:279-90. [PMID: 12287842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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8
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GnRH antagonists and antiprogestins: novel contraceptive options. ADVANCES IN CONTRACEPTIVE DELIVERY SYSTEMS : CDS 1994; 10:207-15. [PMID: 12287839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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9
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[Spermatogenesis protection: myth or reality?]. CONTRACEPTION, FERTILITE, SEXUALITE 1993; 21:744-8. [PMID: 12287596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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10
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[Male contraception: future directions]. REFERENCES EN GYNECOLOGIE OBSTETRIQUE 1993; 1:312-8. [PMID: 12288153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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11
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Looking for the "male pill". NETWORK (RESEARCH TRIANGLE PARK, N.C.) 1992; 13:20-3. [PMID: 12317724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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12
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New male contraceptive entering clinical trials worldwide. CONTRACEPTIVE TECHNOLOGY UPDATE 1989; 10:142-3. [PMID: 12342588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
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13
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Abstract
In this study, immunochemical techniques were employed to examine the guinea pig (GP) testicular proacrosin-acrosin system. Monospecific polyclonal antibodies to the highly stable enzymatically active 34,000 molecular weight form of GP testicular acrosin were generated. Western blot analysis of acid extracts prepared from snap-frozen freshly excised GP testes revealed two major immunoreactive bands with mol. wts of approximately 62,000 and 48,000 and one minor band with an approximate mol. wt of 54-56,000. The 62,000 mol. wt molecule identified is in close agreement with the previously reported mol. wt for purified GP testicular proacrosin. Western blot analysis of different species of testicular acid extracts demonstrated the evolutionary relatedness of the proacrosin-acrosin systems since immunoreactivity was observed primarily with acid extracts from rodent species (rat, mouse and hamster) and not with extracts from evolutionarily less-related species (goat, ram and bovine). The majority of the cross-reactivity observed was characterized by immunoreactivity with the 62,000 and 48,000 mol wt molecules. The only species which exhibited cross-reactivity with the 54-56,000 mol. wt protein was rat. In addition, the iso-immunogenic and aspermatogenic properties of the 34,000 mol. wt form of GP testicular acrosin were examined. One out of five Hartley and one out of seven Strain 2 female GPs immunized and boosted with a total of 200 micrograms of purified protein exhibited increased levels of circulating anti-acrosin iso-antibodies. The antigenic specificity of the iso-antibodies observed in the two animals was verified by Western blot analysis. All other female animals, including two strain 13 GPs, exhibited very low or undetectable levels of such antibodies following immunization. One out of three male Hartley GPs immunized with 50 micrograms of the purified protein exhibited typical lesions of experimental allergic orchitis while none of a group of three animals developed lesions at a 5 micrograms dose. Taken together, these results suggest that the 34,000 mol. wt form of GP testicular acrosin is neither a highly potent iso-immunogen nor aspermatogenic autoantigen.
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14
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Paradoxical suppression of spermatogenesis during tamoxifen treatment of oligospermia. Fertil Steril 1988; 49:376-7. [PMID: 2828124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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15
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Suppression of spermatogenesis by testosterone in adult male rats: effect on fertility, pregnancy outcome and progeny. Biol Reprod 1984; 31:221-30. [PMID: 6089920 DOI: 10.1095/biolreprod31.2.221] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The relationship between decreasing spermatogenic activity and fertility, pregnancy outcome and the progeny is poorly understood. To study this relationship a model where testosterone is given by a sustained release device is used. Adult male Sprague-Dawley rats received empty or testosterone-filled implants measuring 0.5, 1.0, 2.0, 3.0, 4.0 and 8.0 cm. On Day 90 and again on Day 104 each male was exposed to two females in proestrus. Twenty days later the females were killed. Corpora lutea, implantation sites, resorptions and live normal and abnormal fetuses were counted. Sperm counts in the caput-corpus region of the epididymis in the 3.0-, 4.0- and 8.0-cm testosterone treatment groups were 12.6%, 3.0% and 29.9% of control, while those in the caudal region were 19.8%, 4.0% and 50.8% of control, respectively. The number of females with spermatozoa in the vagina after breeding was significantly diminished only in animals treated with the 4.0-cm testosterone implants (control, 95.8%; 4.0-cm, 50%) while the number of pregnant females per sperm-positive females was markedly reduced in the females mated with both the 3.0-cm and 4.0-cm testosterone implants (control, 82.6%; 3.0-cm, 10.0%; 4.0-cm, 7.7%). There was no effect on the numbers of corpora lutea, on the incidence of pre- or post-implantation loss, malformations, or on the numbers of pups/litter. Individual animals with a decrease in caudal epididymal spermatozoal reserves to less than 5 million, however, are infertile. A decrease in epididymal spermatozoal reserves mediated by testosterone does not cause an increase in teratogenicity in the resultant progeny.
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16
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[Determination of fructose in sperm: application in the monitoring of a male hormonal contraceptive]. FEUILLETS DE BIOLOGIE 1984; 25:19-22. [PMID: 12340365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
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17
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Different approaches in contraception. CONTRACEPTIVE DELIVERY SYSTEMS 1984; 5:15 p. [PMID: 12266639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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18
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[Contraceptive development for the future]. CONTRACEPTION, FERTILITE, SEXUALITE 1984; 12:769-79. [PMID: 12313176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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19
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Contraceptive potential of analogs of LH-RH. NETWORK (RESEARCH TRIANGLE PARK, N.C.) 1984; 6:7-8. [PMID: 12266403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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20
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Birth control techniques in China. CHINA POPULATION NEWSLETTER 1983; 1:1-7. [PMID: 12312957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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21
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[Structure and function of the male gonads after cadmium poisoning]. POSTEP HIG MED DOSW 1983; 37:215-30. [PMID: 6320147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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22
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Male contraceptive sought. PLANNED PARENTHOOD REVIEW 1983; 3:8-9. [PMID: 12265637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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23
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[Current data on nonsurgical male contraception]. CONTRACEPTION, FERTILITE, SEXUALITE 1982; 10:825-35. [PMID: 12264584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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24
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The search for male contraception. Men are different. RF ILLUSTRATED 1982:29-31. [PMID: 12264477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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25
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Ability of autoclaved BCG and extracts to induce aspermatogenesis. Indian J Med Res 1981; 74:251-7. [PMID: 6273313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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26
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Sperm suppression with monthly injections of medroxyprogesterone acetate combined with testosterone enanthate at a high dose (500 mg). INTERNATIONAL JOURNAL OF ANDROLOGY 1981; 4:235-45. [PMID: 6265380 DOI: 10.1111/j.1365-2605.1981.tb00707.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The combination of an initial injection of 1000 mg of depot medroxyprogesterone acetate and 500 mg of testosterone enanthate, followed by monthly administration of 150 mg and 500 mg of the same drugs, was tested in 10 healthy males aged 28 through 39, with pre-treatment sperm counts of 50 x 10(6)/ml or more. Eight of the subjects achieved azoospermia, and the sperm counts of the other two declined 0.09 ad 5 million/ml. This last subject was highly refractory to treatment as his sperm density recovered to 27 million sperm/ml at the 6th month of continuous therapy. FSH was severely depressed during the entire treatment period. LH fell to 30--40% of normal values in the first two months and then showed a slow recovery during maintenance treatment. Testosterone measured one month after each injection was between 10 and 30% of pre-treatment values. Three of the subjects had increased libido and potency, none had decreased sexual drive or potency. All subjects gained weight with the average gain being 6 kg. The increase in the dose of testosterone enanthate to 500 mg/ng did not improve the results as compared to previous trials using lower doses of TE.
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Inhibition of progestational activity for fertility regulation. RESEARCH FRONTIERS IN FERTILITY REGULATION : RFFR 1981; 1:1-14. [PMID: 12179622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
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28
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[Research on acrosine: a good track toward contraception?]. CONTRACEPTION, FERTILITE, SEXUALITE 1980; 8:861-2. [PMID: 12336588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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29
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[Antihormones and control of male fertility]. CONTRACEPTION, FERTILITE, SEXUALITE 1980; 8:867-70. [PMID: 12336591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
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30
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Male contraception today. IPPF MEDICAL BULLETIN 1980; 14:3-4. [PMID: 12336575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
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31
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[Artificial regulation of the generative functions of men by means of contraceptive agents]. AKUSHERSTVO I GINEKOLOGIIA 1980; 19:259-260. [PMID: 6247930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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32
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[A male oral contraceptive from China: Gossypol]. PRO FAMILIA INFORMATIONEN 1979; 5:21-2. [PMID: 12261869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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33
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34
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[Male contraception]. CONTRACEPTION, FERTILITE, SEXUALITE 1979; 7:349-52. [PMID: 12335902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
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35
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Effect of Koen--Chai or Chinese celery (Apium graveolens) on spermatogenesis. JOURNAL OF THE MEDICAL ASSOCIATION OF THAILAND = CHOTMAIHET THANGPHAET 1979; 62:164-73. [PMID: 221607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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36
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[Contraception, knowledge and medical power]. CONTRACEPTION, FERTILITE, SEXUALITE 1979; 7:233-5. [PMID: 12278155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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37
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Abstract
The newly available orally effective testosterone undecanoate (TU) was investigated as a possible means for male fertility control. One of 7 normal volunteers exposed to 80 mg TU three times a day for 10-12 weeks became azoospermic, the remaining showed slightly suppressed or unaffected sperm counts. The insufficient suppression of spermatogenesis in 6 out of 7 subjects may be due to the fact that testosterone levels are only sufficiently high to suppress gonadotropins for some hours after ingestion of the drug.
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38
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[Problems with male contraception. 1. Physiological foundations, male contraception (mechanical procedures, contraceptives)]. FORTSCHRITTE DER MEDIZIN 1978; 96:1447-51. [PMID: 208937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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39
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[Present investigations for the development of male hormonal contraception]. ESTUDIOS DE POBLACION 1978; 3:117-20. [PMID: 12278216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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40
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[Male contraception and vasectomy]. CONTRACEPTION, FERTILITE, SEXUALITE 1977; 5:335-42. [PMID: 12260083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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41
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An overview of male sterilization. TAEHAN PINYOGIKWA HAKHOE CHAPCHI = THE KOREAN JOURNAL OF UROLOGY 1976; 17:49-62. [PMID: 12179579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
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42
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[Immunological processes with contraceptive effect from an andrological viewpoint]. ZEITSCHRIFT FUR HAUTKRANKHEITEN 1975; 50:859-63. [PMID: 176834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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43
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Experimental allergic aspermatogenic orchitis. 1. Isolation of a spermatozoal protein (AP1) which induces allergic aspermatogenic orchitis. J Biol Chem 1975; 250:6141-50. [PMID: 238998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A unique highly soluble aspermatogenic protein (AP1) was isolated from guinea pig testes and was shown by immunofluorescence to occupy the outer surface of the sperm acrosome. This protein is a potent inducer of allergic orchitis and aspermatogenesis; as little as 0.2 mug induced orchitis in 60 percent of guinea pig tested. The AP1 protein, relatively small and neutral, is stable under acid conditions, but at pH 8.6 shows a variety of forms due either to aggregation or polymorphism. The purified AP1 protein appeared homogeneous by polyacrylamide gel electrophoresis at pH 2.7 and in sodium dodecyl sulfate and by immunoelectrophoresis using rabbit antisera to either the purified protein or the testes extract. It also showed a single band on immunodiffusion over a wide concentration range. The purification procedure consisted of delipidation with chloroform/methanol (2/1); acid extraction at pH 3.0; precipitation with 85 percent saturated ammonium sulfate; trichloroacetic acid extraction and gel filtration on Bio-Gel A-1.5; gel filtration on Bio-Gel P-10; chromatography on CM52 cellulose; and preparative gel electrophoresis at pH 2.7. Approximately 20 mg of purified AP1 protein were obtained from 5000 g of wet guinea pig testes. The AP1 protein induced an autoimmune disease characterized by infiltration of mononuclear cells around and within the seminiferous tubules (orchitis), followed by extensive damage and destruction of the germinal cells (aspermatogenesis). The course of the disease induced by this protein (0.5 to 1 mug) was essentially identical with that seen with whole testicular tissue or other purified fractions.
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44
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The nitrofurans as sperm immobilising agents: their tissue toxicity and their clinical application. BRITISH JOURNAL OF UROLOGY 1975; 47:459-62. [PMID: 171024 DOI: 10.1111/j.1464-410x.1975.tb04008.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Nitrofurantoin sodium and nitrofurazone in certain critical concentrations have the ability to cause sperm immobilisation. Intraoperative vas irrigation with these solutions in 24 patients have produced sterility in the immediate postoperative period.
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45
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Evaluation and mode of action of nonsteroidal antiestrogens. JOURNAL OF SCIENTIFIC AND INDUSTRIAL RESEARCH 1975; 34:336-352. [PMID: 12259719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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46
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47
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Australian scientists develop male contraceptive. JAMA 1974; 228:1043. [PMID: 12333267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
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48
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[Male contraception]. CONTRACEPTION, FERTILITE, SEXUALITE 1974; 2:5-9. [PMID: 12276959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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49
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[Anti-spermatogenic effect of seminal ribonuclease (BS-1 RNase)]. BOLLETTINO DELLA SOCIETA ITALIANA DI BIOLOGIA SPERIMENTALE 1973; 49:1439-44. [PMID: 4371801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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50
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Chemosterilant action of trimethylphosphate in rodents. Br J Pharmacol 1969; 37:531P. [PMID: 12332193 PMCID: PMC1703712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023] Open
Abstract
Trimethylphosphate, the simplest tri-alkyl ester of phosphoric acid, produces marked antifertility effects in experimental male rodents (Jackson and Jones, 1968). The predominant effect is the "functional" sterilizing action involving spermatids from which intact motile but incompetent sperm continue to be produced. Relatively high doses are required in the mouse (5 X 1 gm/kg orally), whereas it is effective in the rat at 1/10 of this level. Trimethylphosphate is remarkable in that it possesses no anticholinesterase activity, is freshly soluble and stable in water, is effective orally, and has a high level of tolerance. Whereas 500 mg/kg orally render male rats sterile for the ensuing 3 weeks, 5 times this amount, although tolerable, completely disorganizes spermatogenesis without damaging tubular architecture. Such treated rats remain infertile for 20-25 weeks, apparently retaining sexual activity, though a proportion appear to be more permanently sterilized. Rats treated weekly at 5 X 100 mg/kg orally for over 1 year have remained sterile but recover fertility 3-5 weeks from terminating treatment. "Side effects" so far observed are a sedative action and, towards 1 year of treatment, hind leg paresis, although 5 times this dose rate caused progressive loss in weight. Using phosphorus-32-trimethylphosphate the sole phosphorus-containing metabolite is dimethylphosphate (Jackson and Jones, 1968), which has no antifertility activity. With carbon-14-trimethylphosphate, S-methyl cysteine was identified as a urinary metabolite, indicating that trimethylphosphate is involved, at least in its detoxification process, as an alkylating agent. The antifertility action of trimethylphosphate is probably related to methyl alkylation. This would bring it into line with the methyl ester of methanesulphonic acid which also produces the "functional" type of sterility in rats and mice (Jackson, 1964). Like methyl methanesulphonate (Partington and Bateman, 1964), trimethylphosphate in substerilizing doses induces so-called dominant lethal mutations. Preliminary structure/activity studies have shown that tri-n-propyl- and tri-iso-propylphosphates do not affect the fertility of male mice (5 X 1 gm/kg orally). Both these esters together with tri-n-propyl- and tri-n-butyl-phosphates still have the capacity to alkylate, and like trimethylphosphate, the only metabolites in the rat were the di-alkylphosphates and corresponding S-alkyl cysteines. Whereas all these substances interact with cysteine in vitro, only trimethylphosphate reacts readily with glutathione. This might be pertinent to its biological activity.
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