Fertility in rats immunized with steroid-free bovine follicular fluid

Inhibin is a gonadal hormone that inhibits the release of follicle stimulat ing hormone (FSH) from the anterior pituitary gland. The objective of this study was to determine whether active immunization of male and female rats against inhibin rich, steroid-free bovine follicular fluid would increase i nhibin antibody titre, onset of female puberty, pregnancy rate, litter size , testis weights, testosterone concentration and serum FSH. Immunization of rats with steroid free bovine follicular fluid stimulated production of an ti-inhibin antibodies that immunoneutralized endogenous inhibins and increa sed levels of circulating FSH in immunized males. Inhibin immunoneutralizat ion resulted in early vaginal opening in immunized females compared with co ntrols and pregnancy rates were increased when immunized female rats were m ated with immunized males. However, serum testosterone, testis weights and potential litter size remained unchanged. We conclude that methods to immun oneutralize inhibin may have merit as therapeutic procedures to enhance rep roductive performance in domestic animals.