Nearly 2000 analogs of luteinizing hormone (LH)-releasing hormone (RH) have been synthesized since 1971. This paper reviews new developments of contraceptive methods based on these analogs. Approaches to female contraception based on LH-RH agonists have the advantage of reversibility, but have been impeded by problems such as bleeding irregularities, nonuniform inhibition of follicular maturation, and effects of unopposed estradiol secretion on the endometrium. Moreover, careful timing is required for administration of these agonists. Spermatogenesis was inhibited as a result of administration of LH-RH agonists ot men, but the fall in testosterone levels produced impotence and hot flashes. The approach based on combined administration of LH-RH agonsits and testosterone for male contraception requires extensive investigation. Research has also aimed to use LH-RH antagonists to block the midcycle surge of LH and follicle-stimulating hormone (FSH) necessary for ovulation; however, the results of longterm toxicity studies must be awaited. Experiments in rats suggest that antagonists may inhibit spermatogenesis as well. The most convenient and effetive method of administering LH-RH agonsits appears to monthly intramuscular injection of microcapsules made from a biodegradable biocompatible polymer and designed for controlled release over a 30-day period. Intranasal administration also holds promise.
|Original language||English (US)|
|Number of pages||2|
|State||Published - Sep 1 1984|
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