Comparison of methods to stimulate ovarian follicular growth in cynomolgus and African green monkeys for collection of mature oocytes.

The objective was to compare various gonadotropin-based methods to stimulate ovarian follicular growth in female cynomolgus (n=16) and African green monkeys (n=8) for collection of mature oocytes. On the 1st day of menstruation, the monkeys were treated with 3.75mg leuprorelin acetate (a GnRH agonist). Starting 2–3 weeks later, ovarian follicular growth was stimulated as follows: (a) 25IU/kg of human FSH (hFSH) in a glycerol solution given once daily for 9d; (b) 200IU of eCG given six times during a 9-d interval; (c) 75IU/kg hFSH in a glycerol solution given three times (72h intervals) during a 6-d interval. In addition, the monkeys were given 1200 or 4000IU of hCG 36h (Methods A and B) or 60h (Method C) after the last gonadotropin treatment, and oocyte collection was attempted 36–38h after hCG. Although there were no significant differences among methods in the number of oocytes collected, in cynomolgus monkeys, hFSH (Methods A and C) was better than eCG (Method B; 12 and 10 versus 7 mature oocytes, respectively), whereas in African green monkeys, eCG (Method B) was more effective than hFSH (Method A; 12 versus 7 mature oocytes). Furthermore, in cynomolgus monkeys, Method C was nearly as effective as Method A; using a glycerol solution as a solvent decreased the frequency of hFSH administration from nine to three times. In conclusion, in cynomolgus and African green monkeys, ovarian response depended on the species and on the individual, and in cynomolgus monkeys, hFSH in a glycerol solvent was effective.