Effect of immunization with synthetic peptide corresponding to region 1-17 of human seminal plasma inhibin on fertility of male rats.

Immunization of adult male rats with a synthetic peptide corresponding to the region 1-17 of human seminal plasma inhibin (hSPI) resulted in agglutination of epididymal sperm, severely affecting the fertility of the animals (75% reduction in fertility as compared to control). This effect was found to be dependent on the antibody titer to hSPI. There was a significant rise in circulating follicle-stimulating hormone levels, with luteinizing hormone and testosterone levels remaining unaffected. The histology of the testes and other reproductive organs revealed that these organs remained unaltered. The N-terminal 1-17 amino acid peptide of hSPI may hold promise as an immunogen for male immunocontraception.