Ovarian stimulation and ultrasound-guided oocyte retrieval in baboon (Papio cynocephalus anubis) during pituitary suppression with a GnRH agonist

The objective of this study was to investigate whether baboon females respond to an ovarian stimulation protocol incorporating pituitary suppression with a GnRH agonist (GnRHa) and either highly purified human FSH (hphFSH) or recombinant human FSH (rhFSH) with follicular development and oocyte maturation. A modified human ovulation induction protocol was applied to 5 adult female baboons with a history of regular menstrual cycles (33–34 days). A long-acting GnRHa implant containing goserelin acetate was placed subcutaneously (s.c.) on Days 22–24 of their menstrual cycle. Concentrations of serum oestradiol (E2), progesterone (P4) and human FSH were obtained by ELISA. Menses occurred ∼ 10 days after GnRHa implantation. Daily hphFSH or rhFSH (75 IU i.m.) treatments were started ∼ 10 days following menses. When the majority of follicles were ≥ 5 mm in diameter and the E2 levels had reached a maximum, hCG (2000 IU i.m.) was administered to induce final maturation of oocytes and ovulation. Thirty to 34 h after hCG administration, transabdominal follicular aspiration was performed using a variable frequency transvaginal transducer with ultrasound. A total of 71 oocytes were collected from 4 animals (average: 17). The meiotic maturity of oocytes was evaluated 3 h after retrieval. Ninety-one percent of oocytes were in metaphase 2 and of grades I and II which are appropriate for in vitro insemination.