IMMUNOLOGICAL CASTRATION USING A GONADOTROPIN-RELEASING-HORMONE ANALOG CONJUGATED TO PPD

The importance of gonadotrophin-releasing hormone/luteinizing hormone- releasing hormone (GnRH/LHRH) to reproductive function is illustrated when animals immunized with GnRH produce a high humoral immune respons e which can achieve a humane alternative to surgical castration. In th is paper the male rat was used as a model Rats were immunized with an analogue of GnRH-GnRH-glycys-in both its free form and conjugated to t he carrier PPD. Pre-immunization priming with BCG was compared with no n-BCG priming. The results showed that BCG priming in the absence of a djuvant, allowed a sufficient reduction in testosterone levels to occu r without severely affecting gonadal changes. Immunization in conjunct ion with adjuvant resulted in high antibody titres, a decrease in test osterone levels, gonadal atrophy and a reduction in spermatogenesis. A lteration of the dose levels of the analogue and the long-term effects of immunization on gondal function were also investigated.