Follicle-stimulating hormone priming of rhesus monkeys enhances meiotic and developmental competence of oocytes matured in vitro.

The objective of this study was to determine the effects of FSH priming of rhesus monkeys upon meiotic and developmental capacity of oocytes in vitro. FSH-primed monkeys (n = 9) received injections of porcine FSH for 6-7 days. Germinal vesicle-stage oocytes (n = 402) were obtained from dissected follicles. All oocytes were cultured for 36-40 h, inseminated, and incubated until developmental arrest. Greater (p < or = 0.001) percentages of cumulus-enclosed oocytes from FSH-primed vs. nonstimulated monkeys completed meiotic maturation (74 vs. 41%), activated/fertilized (85 vs. 61%), and cleaved from the 2-4-cell (79 vs. 38%) through the morula (29 vs. 1%) stages. Blastocysts (4%) were obtained only from FSH-primed monkeys. Compared with their cumulus-enclosed counterparts, denuded oocytes were compromised (p < or = 0.05) in completing nuclear maturation and cleaving in vitro. The meiotic and developmental capacity of denuded oocytes from FSH-primed monkeys exceeded (p < or = 0.01) those of denuded oocytes from nonstimulated monkeys. Denuded oocytes from FSH-primed monkeys were more (p < or = 0.01) competent to cleave beyond 8 cells than cumulus-enclosed oocytes from nonstimulated monkeys. Meiotic and developmental competence was similar between oocytes with or without cytoplasmic vesicles. Thus, FSH priming of monkeys enhances nuclear and cytoplasmic maturation of oocytes in vitro, and resulted in production of the first in vitro-matured/in vitro-fertilized primate blastocysts in vitro.