Ovulation Induction by Gonadotropin and Prostaglandin Treatments of Rhesus Monkeys and Observations of the Ova

Abstract
Mature female rhesus monkeys were treated with pregnant mare serum gonadotropin (PMS), human chorionic gonadotropin (hCG) and prostaglandins (PGE1, PGE2 and PGF2.alpha.) to develop a reliable method for inducing superovulation. Optimal results followed daily i.m. injections of 100 IU PMS [pregnant mare''s serum gonadotropin] on menstrual cycle Days, 4, 5, 6 and 7 followed by 200 IU PMS on Days 8, 9, 10 and 11, 4000 IU of hCG on Day 12 and 5 mg of either PGE1 or PGE2 on Day 13. This treatment resulted in 1-29 ovulations in each of 38 animals and only 1 animal failed to ovulate upon initial exposure to this regimen. Most ovulations occurred between 24 and 48 h after the PG injection; therefore, 36 h after PG was taken as the estimated ovulation time for subsequent insemination experiments. The gonadotropin treatment alone and, followed by 5 mg PGF2.alpha., resulted in ovulation induction in only 2 of 5 monkeys and 1 of 3 monkeys, respectively. Sperm, obtained by electroejaculation of rhesus males, were washed and surgically introduced directly into the uterine cavity of 22 monkeys at intervals before and after the estimated ovulation time. Only 14 of 76 ova recovered at varying intervals after insemination exhibited superficial light microscopic evidence of penetration of fertilization; however, upon ultrastructural analysis the occurrence of normal fertilization could not be confirmed. Ultrastructural features, e.g., degenerative changes in ovulated ova along with aberrant ovientation of the meiotic spindles in secondary oocytes obtained from follicles prior to ovulation, were consistent with the idea of prolonged retention of oocytes within follicles prior to their release in these experiments. Data suggest the possibility of asynchrony in ovum maturation and ovulation induced by gonadotropins and E series PG.