Immunization of dogs with bovine luteinizing hormone

Abstract

Testicular, thyroidal, and adrenal activities were measured in male Beagle dogs immunized against a purified bovine luteinizing hormone (NIH LH B5) for 15 or 52 wk. Circulating antibodies were associated with atrophy of the testes, epididymides and prostate gland. The ability to ejaculate was impaired by 2 to 5 wk after the first immunizing dose. Libido and penile erection were not visibly affected, although blood levels of androgens were lowered. The effects of immunization were apparent by high levels of antibodies and reproductive dysfunction for as long as 52 wk in 3 of 4 dogs in the longterm study. Immunization did not affect gravimetric, histologic, or hormonal measures of function of the thyroid or adrenal glands. Immunization against luteinizing hormone specifically interfered with endogenous gonadotropins by immunologic neutralization of their biologic effects. High levels of antibodies 271 days after the last immunizing dose may be an indication of a secondary, anamnestic response to endogenous gonadotropin.