Timing of sequential changes in chromosome configurations during the 1st meiotic division of pig oocytes cultured in vitro.

This study examines the timing of changes in chromosome configurations of pig oocytes derived from small antral follicles of follicular and/or inactive stage donors using modified 199 medium supplemented with gonadotropins (Follicle Stimulating Hormone (FSH), 10 IU/ml; Human Chorionic Gonadotropin (hCG), 10 IU/ml) and Glucosamine (0.539 mg/ml). Oocytes (n = 1,215) were fixed at the end of 3 hourly intervals from 0-48 hr of culture. Results were expressed as the percentage of oocytes at each stage of maturation for each time point. The germinal vesicle (GV) stage was observed for the first 17.6 hr; germinal vesicle breakdown (GVBD) stage between 17.6-26.4 hr; metaphase I (M-I) from 26.4-30.9 hr; anaphase I (A-I) ranged from 30.9-33.4 hr; telophase I (T-I) at 33.4-34.4 hr; and metaphase II (M-II) at 34.4-48 hr.