Active Immunization of Female Rats with Luteinizing Hormone Releasing Hormone (LHRH)

Abstract

Cycling rats were immunized against LHRH. In most of these rats, antibody to LHRH became detectable 20 days after the first immunizing injection and reached a maximum level about 40 days later. The elevation of antibody titers, accompanied by the lengthening of the estrous cycle, resulted in continuous anestrus approximately 50 days after the first injection. Peripheral serum LH declined to nondetectable levels but prolactin was not significantly altered throughout the experimental period. The presence of circulating antibody to LHRH was confirmed by the blockade of ovulation in cycling hamsters after i.v. injection of serum from the immunized rats.