Immunotherapy and fertility control by immunization against gonadotrophin-releasing hormone

Gonadotropin-releasing hormone (GnRH) also known as luteinizing hormone-releasing hormone (LHRH) is a decapeptide released from the hypothalamus. It regulates the secretion of the gonadotropins LH and FSH from the pituitary; these gonadotropins in turn act on the gonads to generate the gametes and sex steroid hormones. GnRH is thus a "master" molecule regulating a cascade of events affecting reproduction and steroid hormone production. Immunization against GnRH blocks these processes and because GnRH is made by both males and females immunization can be used to influence either male or female fertility. Furthermore as the molecule is essentially conserved through evolution immunization against the decapeptide is an effective way of controlling fertility in a variety of mammalian species. This property has been useful in studies determining the efficacy and side effects of vaccines designed to produce antibodies against GnRH. Here the authors review some recent advances in the development of anti-GnRH vaccines and consider some possible therapeutic applications. (authors)