Antral follicle development and in-vitro maturation of oocytes from macaques stimulated with a single subcutaneous injection of pregnant mare's serum gonadotrophin.

A single s.c. injection of 1000 IU of pregnant mare's serum gonadotrophin (PMSG) stimulates the growth of multiple antral follicles in cynomolgus monkeys (Macaca fascicularis). The number of cumulus-enclosed oocytes (CEO) from six non-stimulated controls was 36 (mean = 6). In contrast, a total of 95 CEO (mean = 31.7) were recovered from three animals stimulated and ovariectomized 3 days later, while 385 CEO (mean = 128.3) were obtained from three animals stimulated and ovariectomized 4 days later. A comparison of the effects of highly purified human follicle-stimulating hormone (FSH), human luteinizing hormone (LH) and human thyroid-stimulating hormone (TSH) on cultures of rhesus monkey (Macaca mulatta) CEO cultured in medium 199 for 48 h showed that FSH and LH stimulated cumulus expansion but had moderate effects on the progression of meiosis. The progression that did occur seldom proceeded beyond the metaphase I stage. Human TSH had no demonstrable effect on cumulus expansion and meiotic progression. In other experiments FSH, LH and oestradiol-17 beta were added jointly to medium CMRL 1066 in which CEO from non-PMSG-stimulated and PMSG-stimulated cynomolgus monkeys were cultured for 48 h. If the CEO were obtained from non-PMSG-stimulated monkeys the hormones caused a significant cumulus expansion, but had only a limited effect on meiotic progression. However, if the CEO were obtained from PMSG-stimulated monkeys there was a significant stimulation of cumulus expansion and meiotic progression. The hormone treatment resulted in a yield of 72.8% metaphase II oocytes compared with 40.9% in the controls.