Influence of Immunization with Luteinizing Hormone Upon the Anterior Pituitary-Gonad System of Rats and Rabbits, with Special Reference to Histological Changes and Biosynthesis of Luteinizing Hormone and Steroids

Active immunization of rats and rabbits with ovine luteinizing hormone (NIH-LH- S7) caused a marked atrophy of the testis, seminal vesicle and prostate, and hypertrophy of the anterior pituitary and adrenal glands. Inhibition of spermatogenesis and of the androgen-producing activity of the testis was observed, while the proliferation and enlargement of the basophilic cells with increased PAS-positive granules in both central and peripheral regions of the anterior pituitary gland were apparent histologically. A radioimmunochemical study on the de novo biosynthesis of LH in the anterior pituitaries of these immunized animals showed a marked increase of amino acid incorporation into the LH fraction. Passive immunization of rats with the rat anti-ovine LH-antiserum, or castration, showed similar changes, while no significant changes were observed in the animals receiving LH without adjuvant. These results suggested that immunization of the animals with ovine LH caused the production of anti-LH-antibody, inhibiting the action of the endogenous LH of the animals, which resulted in the inhibition of androgen production in the testis. The deficiency of androgens caused proliferation of gonadotrophs and increased production of LH in the anterior pituitary gland, similar to the situation after castration. (Endocrinology79: 477, 1966)