Effect of active immunization of pony mares against recombinant porcine inhibin alpha subunit on ovarian follicular development and plasma steroids and gonadotropins.

This research investigates the effect of immunizing pony mares against an inhibin protein on their ovarian follicular development and hormone levels, suggesting a potential method to increase the number of ovarian follicles during their estrous cycle.

Methodology

• The experiment involved two pony mares that were immunized against recombinant porcine inhibin alpha subunit. The immunization procedure took place three times, spaced out with 39 day intervals.
• The researchers established a control by collecting clinical and endocrinological data prior to the immunization treatments.

Findings

• The first significant increase in anti-inhibin presence (the antibodies produced against the inhibin) was observed 27 days following the initial injection.
• Prominent binding activity, representing the effectiveness of the immunization, was achieved by the 12th day after the second booster dose.
• Comparing pre- and post-immunization, a significant increase was observed in the number of all sizes (small, medium, and large) of follicles. However, the ovulation rate remained consistent, implying that though more follicles developed, the actual ovulation process was not positively affected by the immunization.
• Similarly, the average plasma concentration of Follicle Stimulating Hormone (FSH) and estradiol-17beta (a steroid hormone) had considerably increased during the estrous cycle after the immunization.

Conclusion

• The study suggests that immunization against inhibin might serve as a beneficial method to enhance the quantity of ovarian follicles throughout the estrous cycle in pony mares.
• Furthermore, it supports the theory that inhibin performs a substantial function in managing follicular growth via its suppressive impact on FSH secretion in combination with steroid hormones. This hints at the hormonal interplay involved in ovarian follicular development in mares and potentially other mammals.