National Wildlife Research Center (NWRC)
Development of Injectable and Oral Contraceptive Technologies and Their Assessment for Wildlife Population and Disease Management
Gonadotropin-Releasing Hormone Immunocontraception
(NWRC publications on GnRH)
The GnRH vaccine stimulates the production and release of GnRH-specific antibody from the B-cell into the bloodsteam. The antibody circulates throughout the body, and when it reaches the capillary region of the hypothalamus, it comes into contact with GnRH that has diffused into the capillaries after being produced in the hypothalamus. Binding of GnRH to the specific antibody forms large immune-complexes that travel down the hypophysial stalk. Because of their large size, however, the immune-complexes are unable to diffuse out of the blood at the pituitary capillaries. Instead, they remain in the venous blood and leave the pituitary without stimulating the release of LH and FSH. Without the LH and FSH that normally stimulate the synthesis of steroids in the reproductive organs, animals of both sexes remain in an asexual, non-reproductive state. As long as there is sufficient antibody to bind all GnRH circulating in the hypothalamic/pituitary portal system, all sexual activity will be suspended and animals will remain non-reproductive.
Last Modified: March 24, 2010