Effects of active immunization of female rabbits against testosterone.

Prepubertal (immature) and mature female rabbits were actively immunized against testosterone-3-oxime-bovine serum albumin over a period of 11 weeks. The antibody titre was significant in all animals by 5 weeks. The concentration of FSH in prepubertal animals decreased significantly (P less than 0.001) between weeks 1 and 5, but no significant changes were observed in the concentration of LH at any time. After immunization for 8 weeks, there was a significant (P less than 0.05) increase in the serum concentration of androgen and the percentage of bound testosterone also increased (P less than 0.05). The serum concentration of oestradiol increased after immunization for 11 weeks, compared with values at 8 weeks (P less than 0.05) and oestradiol binding also rose by week 5 (P less than 0.01). Libido was not affected and significantly (P less than 0.005) increased numbers of ovulations were noted in immunized animals. These results suggest that immunization of the female rabbit against testosterone may disrupt the normal regulation of follicular maturation.