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  • Title: The search for male contraception. Men are different.
    Author: Steinmann M.
    Journal: RF Illus; 1982 Jun; ():29-31. PubMed ID: 12264477.
    Abstract:
    Research in male chemical contraceptives have uncovered 2 methods of regulating sperm production that are presently in the early testing stages in humans. Regulation of the reproductive system in both men and women is similar. Sexual centers in the upper brain respond to internal and external stimuli by sending signals to the hypothalamic region in the lower brain which then secretes the brain hormone, luteinizing hormone releasing hormone (LHRH). LHRH causes the pituitary gland to release the luteinizing hormone (LH) and the follicle stimulating hormone (FSH) which are named for their function in women. In women, FSH and LH stimulate the ovaries to produce eggs and secrete estrogen and progesterone, causing the uterus to prepare for pregnancy. In men, FSH and LH stimulate the testes to produce sperm and secrete testosterone. The pituitary gland regulates the sex hormone levels by secreting or not secreting LH and FSH. The initial approach to chemical contraception in men has been to develop a method analogous to the mechanism of action in oral contraceptives used for women. Although many different combinations of drugs have been tested, the method has not adequately reduced sperm production. Since the late 1970s, testing has been done with LHRH, and administration of synthetic forms of the hormone or powerful doses of LHRH have been shown to inhibit sperm production. In 1 study, 8 men took daily doses of the hormone for 10 weeks, sperm counts were decreased by 70% and the effect was reversible within a few months after discontinuation of the hormone. LHRH administration also stopped secretion of testosterone. 5 of the 8 men became temporarily impotent. To be a satisfactory contraceptive, LHRH would have to be taken with extra testosterone. Mode of administration for commercial use, level of effectiveness, and potential toxicity have not yet been determined. Gossypol, an impurity in raw cottonseed oil that was accidently discovered in China, is also being tested. A study of 10,000 Chinese taking different versions of the drug by mouth in doses ranging from 10-70 mg/day for 5 weeks to 6 years resulted in an antifertility efficacy of 99.07%. Gossypol stops sperm production without affecting testosterone secretion and it renders maturing sperm in the epididymis immotile. One of the side effects noted in the Chinese study was lowered levels of potassium, causing complaints of lassitude, fatigability, and transient weakness. Reversibility is also questioned, as 10% of 1 group remained sterile for 6 months-4.5 years after discontinuation. Additional research questions on Gossypol concern toxicity, interaction with red blood cells, areas of concentration in the body, and modification of its molecular structure and teratogenic effects.
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