Male oral contraceptive

From Wikipedia, the free encyclopedia

The “male pill” is a colloquial term for a counterpart to the “the Pill” for women, which is a hormonal contraceptive taken daily by the oral (mouth) route of administration. A true male pill, however, will not likely be a hormonal contraceptive. This is because testosterone -- the key hormone required for a male hormonal contraceptive -- has only one orally active formulation, testosterone undecanoate (TU). To maintain sufficient levels of testosterone in the blood, oral TU must be taken twice daily, [1] and even then is not as effective as other testosterone formulations [2].

A true male pill may emerge from other orally active drugs being studied as male contraceptives. There are both plant-based extracts and manufactured drugs under consideration.

Male oral contraceptives are to be distinguished from other non-oral administered forms of experimental contraception, such as the male hormonal contraceptive implant or injection. An implant is a drug-dispensing device placed under the skin. An injection is usually placed intramuscularly using a needle and syringe.

Contents 1 Plants could provide a male pill 2 Pharmaceutical companies are seeking male pill drugs 3 Other targets for male pills are being researched 4 Adjudin in the news 5 References 6 See also 7 External links

[edit] Plants could provide a male pill

• The Chinese plant Tripterygium wilfordii and its botanical cousins contain several orally active compounds that provide male contraception. Pills made from Tripterygium have been used in traditional Chinese medicine for over 1000 years. Researchers are isolating the compounds with contraceptive effects for further research [3].
• When extracts from the seeds of papaya fruits (Carica papaya) were fed to monkeys, the monkeys had no sperm in their ejaculate. Researchers are trying to determine whether papaya seed extracts are safe for use in additional studies [4].
• Oleanolic acid extracted from a South African tree, Eugenia jambolana, reversibly lowers sperm motility without affecting sperm count in rats [5].
• The neem tree (Azadirachta indica), common in India, has many medicinal uses. Very small quantities of neem oil have been successfully tested as an alternative to surgical vasectomy. Fresh neem leaves caused reversible contraception in male rats [6], and there are anecdotal claims of the use of neem leaf extracts as effective male contraception.
• Pills made from gossypol, a compound found in cotton seeds, have been abandoned as a potential male contraceptive because of unreliable reversibility in clinical trials. Researchers have suggested that gossypol might make a good non-invasive alternative to surgical vasectomy [7].

[edit] Pharmaceutical companies are seeking male pill drugs

• Calcium channel blockers such as nifedipine – already approved for men with hypertension – may cause reversible infertility by altering the lipid metabolism of sperm so that they are not able to fertilize an egg [8].
• Miglustat -- also known by its trade name Zavesca –- is already approved for the treatment of Gaucher disease. In male mice, low doses of it cause reversible infertility by decreasing sperm motility [9].
• Researchers are developing analogs of Lonidamine, a drug developed as a cancer treatment which was an effective male contraceptive. Lonidamine’s toxicity disqualifies it as a potential contraceptive, but researchers have formulated several related compounds that are non-toxic and effective, such as Adjudin [10].

[edit] Other targets for male pills are being researched

There are many other targets within the male reproductive system which are good candidates for contraceptive drugs. Half a dozen such targets for a male pill are in very basic stages of research now: Dr. George Witman’s work on sperm tail proteins required for motility [11], Dr. David Clapham’s work on sperm-specific ion exchange channels needed for hyperactivation [12], and Dr. Joseph Hall’s work on sperm head enzymes needed to recognize an egg [13], to name a few. These and other researchers at universities and large pharmaceutical companies are using high-through-put screening to identify small, easily manufactured drugs which are effective treatments for these targets. Docters Morton Hair, Kay Kitteridge, and Fred Wu, three researchers from Manchester, England, found that the combination of an oral contraceptive containing progesterone and wearing a testosterone patch showed no active sperm count after three months. The study was conducted on 23 local men, whose sperm counts gradually returned to normal after they stopped using the pill and patch. [14]

[edit] Adjudin in the news

On October 31, 2006; CBS News reported that the drug Adjudin had made male laboratory rats infertile for 20 weeks and they became fertile again soon after with no side effects for the adults or the babies. Adjudin was mixed with a synthetic type of the sex hormone FSH and injected into the bellies of the rats, because oral intakes of Adjudin alone were too toxic for the rodents. The study came from the Population Council's Center for Biomedical Research in New York city. Years from now, it might be used by humans. [15]

[edit] References

• “An oral regimen of cyproterone acetate and testosterone undecanoate for spermatogenic suppression in men” by MC Meriggiola et al. in Fertility and Sterility, November 1997.
• “Inhibition of spermatogenesis in men using various combinations of oral progestagens and percutaneous or oral androgens” by JF Guerin and J Rollet in the International Journal of Andrology, June 1988.
• “Recent progress in research on Tripterygium: a male antifertility plant” by QS Zhen [sic] et al. in Contraception, February 1995.
• “Chloroform extract of Carica papaya seeds induces long-term reversible azoospermia in langur monkey” by NK Lohiya et al. in the Asian Journal of Andrology, March 2002.
• “The effect of oleanolic acid on sperm motion characteristics and fertility of male Wistar rats” by MC Mdhluli and G van der Horst in Laboratory Animal, October 2002.
• “Male antifertility activity of Azadirachta indica in mice” by VY Deshpande et al. in the Journal of Postgraduate Medicine, July 1980.
• “Gossypol: a contraceptive for men” by E Coutinho in Contraception, April 2002.
• “Pregnancy following discontinuation of a calcium channel blocker in the male partner” by A Hershlag et al. in Human Reproduction, March 1995.
• “Long-term non-hormonal male contraception in mice using N-butyldeoxynojirimycin” by CM Walden et al. in Human Reproduction, May 2006.
• “AF-2364 [1-(2,4-dichlorobenzyl)-1H-indazole-3-carbohydrazide is a potential male contraceptive: a review of recent data”] by CY Cheng et al. in Contraception, October 2005.
• “Novel role for a sterol response element binding protein in directing spermatogenic cell-specific gene expression” by H Wang et al. in Molecular and Cellular Biology, December 2004.
• “CatSper1 required for evoked Ca2+ entry and control of flagellar function in sperm” by AE Carlson et al. in the Proceedings of the National Academy of Sciences, December 2003.
• “Purification and characterization of protein D/E, a putative sperm-binding protein involved in fertilization” by JC Hall and CE Tubbs in Preparative Biochemistry and Biotechnology, November 1997.

[edit] See also

• Male contraceptive
• Gossypol

[edit] External links

• A summary of the Population Council’s work on potential male contraceptives, including the Lonidamine analog Adjudin