Adult female rats were actively immunized with sperm-coating protein (
10.4 KDa) human seminal plasma inhibin (HSPI). Following 8 weeks of im
munization at 2.5 ug and 5 ug doses of HSPI with Freund's complete adj
uvant, antifertility effects were observed in 63% (5/8) and 88% (7/8)
of animals, respectively. Estrous cycle was not affected in experiment
al group. Thus, the present study suggests the potential use of HSPI f
or immunocontraception in females.