Effect of hCG in the Presence of hCG Antibodies on the Follicle, Hormone Concentrations, and Oocyte in Mares

Abstract

Follicle blood flow, follicular-fluid and plasma hormone concentrations, and oocyte quality were studied 30 h after an ovulation-inducing hCG treatment when the pre-ovulatory follicle was 32 mm. Mares were grouped as positive (n = 16) and negative (n = 44) for hCG antibodies before the experimental hCG treatment. Percentage of the follicle wall with blood flow signals was less (p < 0.05) in the antibody positive group than in the negative group. The concentrations of follicular-fluid oestradiol and free IGF1, and plasma oestradiol were greater (p < 0.001), and follicular-fluid progesterone (p < 0.001) and plasma LH (p < 0.02) were less in the antibody-positive group than in the negative group. For recovered oocytes at 30 h (n = 37), the antibody-positive group had fewer (p < 0.001) mature (MII) oocytes than the antibody-negative group. Results were attributable to highly effective neutralization of the hCG in the antibody-positive group.

Effects of Induction of Ovulation with GnRH or hCG on Follicular and Luteal Blood Flow in Holstein–Friesian Heifers

“…In addition, it has been reported that oocyte quality was better when hCG concentrations were higher in the follicular fluid (Laufer et al. 1984; Siddiqui et al. 2009a).…”

Relationship of vascular perfusion of the wall of the preovulatory follicle to in vitro fertilisation and embryo development in heifers

“…In summary, greater vascularity of the preovulatory follicle has been associated with greater follicular diameter (women: Bhal et al 1999, mares: Silva et al 2006, heifers: Siddiqui et al 2009b, retrieval rate of oocytes (women: Bhal et al 1999, mares: Ginther et al 2007, retrieval rate of mature oocytes (mares: Ginther et al 2007, Siddiqui et al 2009a, fertilisation rate (women: Bhal et al 1999Bhal et al , 2001) and pregnancy rate (women: Bhal et al 1999, Coulam et al 1999, Huey et al 1999, Du et al 2006, Shrestha et al 2006, mares: Silva et al 2006, heifers: Siddiqui et al 2009b, and lower incidence of triploidy (women: Bhal et al 2001). Studies on the relationship between blood-flow characteristics of the wall of the preovulatory follicle to oocyte retrieval and maturity have been done only in women and mares, and studies on fertilisation and embryo development of the oocyte after IVF have been done only in women.…”

“…Follicular blood-flow assessment by colour Doppler ultrasonography has been used in mares after hCG treatment to study follicle vascularity in regard to maturity of the preovulatory follicle and the oocyte , and oocyte quality in presence of circulating hCG antibodies (Siddiqui et al 2009a). The vascularity tended to be greater for preovulatory follicles that contained a mature oocyte .…”

“…The vascularity tended to be greater for preovulatory follicles that contained a mature oocyte . Mares that were negative for hCG antibodies had greater frequency of mature oocytes and greater vascularity of the follicular wall (Siddiqui et al 2009a). Colour Doppler assessment of blood flow in the follicular wall in mares (Silva et al 2006) and heifers (Siddiqui et al 2009b) indicated that follicular blood flow was greater in the animals that became pregnant after insemination.…”

A single intramuscular injection of Gonadorelin [6-D-Phe] induces ovulation in the mare

“…The formation of hCG-antibodies as reported by Duchamp et al in 1987 may enhance the time of ovulation after injection or prevent the ovulation at all. Another study (Siddiqui et al 2009) considers hCG-antibodies capable of neutralizing the injected hCG within 30 hours. The use of the GnRH analogue deslorelin (Ovuplant ® ) should cause prolonged intervals between the induced ovulation and the subsequent ovulation if the mare is not getting pregnant and the implant is not removed after the induced ovulation (McCue et al 2002).…”