Effect of HCG in the presence of HCG antibodies on the follicle, hormone concentrations, and oocyte in mares.

The research paper discusses the impact of Human Chorionic Gonadotropin (hCG) in the presence of hCG antibodies, on several factors related to reproductive health in horses, including follicle blood flow, hormone concentrations, and the quality of egg cells.

Research Setup

• The researchers examined the follicle blood flow, follicular-fluid and plasma hormone concentrations, and the quality of ovum (oocyte) 30 hours after administering an ovulation-inducing hCG treatment, when the pre-ovulatory follicle size was 32 mm.
• The subjects for the experiment were divided into two groups – those that tested positive (16 in number) and those that tested negative (44 in number) for hCG antibodies prior to the experimental hCG treatment.

Findings

• It was observed that the percentage of the follicle wall exhibiting blood flow signals was less in the group that tested positive for hCG antibodies than those that tested negative. This means there was diminished blood flow towards the pre-ovulatory follicle in mares that had the said antibodies present.
• Furthermore, the concentrations of follicular-fluid oestradiol and free IGF1 hormones, and plasma oestradiol hormone were found to be higher in the antibody-positive group than in the antibody-negative group.
• Conversely, follicular-fluid progesterone and plasma LH hormones were found to be lower in the antibody-positive group than in the antibody-negative group.
• When it came to the recovery of oocytes at the 30-hour mark, the antibody-positive group yielded fewer mature (MII) oocytes than the antibody-negative group.

Conclusion

• The results of the study were primarily attributed to the highly effective neutralization of the hCG treatment by the hCG antibodies present in the antibody-positive group. This implies that the presence of hCG antibodies in mares can significantly influence factors like follicle blood flow, hormone concentrations, and the quality of egg cells, rendering hCG-induced ovulation ineffective.