[Effect of LHRH crasis protein as vaccine on the reproductive function of male rats].

Objective: To investigate the effect of Trx-LHRH, a new GnRH crasis protein, on antibody production and male reproductive function.

Methods: Trx-LHRH produced in vitro with a new crasis gene which crasised Trx gene and GnRH gene together, was used as vaccine, and hydroalaminum base as adjuvant, in adult SD rats. After 5 weeks of the first treatment, the same dosage was used again to enhance the effect of vaccine. Antibody level was measured by ELISA, and androgen level by RIA.

Results: Trx-LHRH induced successfully the polycolonal antibody at the level of 1 :1 280 approximately 2 560 after 4 weeks of the first treatment, and 1 : 2 000 after 6 weeks of the enhanced treatment. Testosterone level was reduced significantly (P < 0.01) by ELISA, but there was reasonable variation among individuals. Sperm count was also reduced by Trx-LHRH treatment.

Conclusion: Trx-LHRH can be used as effective vaccine to induce antibody production, and at the same time, restrain the function of hypothatamas-pituitary-testis axis in vivo.