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NETWORK. 1992 Aug; 13(1):20-3.Researchers are pursuing 2 approaches to developing a male contraceptive drug. 1 approach centers around suppression of sperm production the other around blocking conception. Researchers are looking at introducing hormonal contraceptives into men's bodies via injections or implants to stop sperm production. Both forms of these possible male contraceptives will not be available for many years, however. A WHO study on testosterone enanthate of men in 7 countries reveals total suppression of sperm production occurred in almost all the Asian men, but only about 60% suppression occurred in other ethnic groups. A current WHO study is examining whether a hormonal contraceptive which is not 100% effective can be useful if it would be more effective than barrier methods. The Population Council is conducting research on 2 capsule implants with 1 capsule releasing luteinizing hormone releasing hormone 13 to halt sperm production while the other releases an androgen to maintain sex drive. Animal tests indicate complete contraception with no side effects. The other possible means of suppressing sperm production is administration of a cottonseed oil extract called gossypol which appears to stop sperm production thereby eliminating the need for concurrent androgen administration. Yet it does cause potassium depletion in some men which can result in arrhythmias. An antifertility vaccine comprises the 2nd approach. Several US researchers are exploring an antifertility vaccine to produce antibodies only to the specialized sperm surface needed to attach to the egg. The 1st antifertility vaccine would probably be in pill form and a woman's contraceptive since it is earlier to target the smaller number of sperm in the oviduct than in the testes.
CONTRACEPTION. 1992 Aug; 46(2):103-4.WHO formed its Task Force on Methods for the Regulation of Male Fertility in 1972. Its charge is developing safe, effective, reversible, and affordable contraceptive methods for developing countries. The research focus is on suppression of sperm production. The research strategy consists of 3 parts: suppression of secretion of the pituitary gonadotropin hormones, recouping circulating androgen to physiological levels without prompting spermatogenesis, and determining the functional ability of residual sperm if treatment does not bring about azoospermia in all cases. A task Force study reveals that men of various ethnic groups respond to testosterone contraceptives differently. Other clinical research involved an androgen with a progestogen such as DMPA. Since steroids are basically inexpensive to produce they may prove to be beneficial and affordable to national family planning programs in developing countries. Gonadotropin releasing hormone (GnRH) antagonists proved to be relatively effective in suppressing gonadotropins and sperm production in animals. Scientists working on developing GnRH antagonists should strive to formulate a reversible contraceptive with no side effects which requires limited injections. The Task Force carried out a study in bonnet monkeys with the GnRH agonist buserelin in which buserelin suppressed spermatogenesis for 3 years and, after treatment, testicular function was entirely restored. Subsequent mating trials indicated they were fertile. The Task Force planned to follow the study with a GnRH antagonist. The 1st international gathering on GnRH analogues in China served to bring together scientists the world over to meet and to collaborate in developing new drugs for contraceptive use.