DEVELOPMENTAL POTENTIAL OF EMBRYOS PRODUCED BY IN-VITRO FERTILIZATIONFROM GONADOTROPIN-RELEASING-HORMONE ANTAGONIST-TREATED MACAQUES STIMULATED WITH RECOMBINANT HUMAN FOLLICLE-STIMULATING-HORMONE ALONE OR IN COMBINATION WITH LUTEINIZING-HORMONE

We previously demonstrated, in luteinizing hormone (LH)deficient macaq ues, that follicular growth and maturation occurred with administratio n of exogenous (recombinant human) follicle stimulating hormone (r-hFS H) alone, and that the oocytes recovered fertilized at a notably highe r rate than their counterparts from animals receiving both r-hFSH and r-hLH (Zelinski-Wooten et al., 1995), Here, the developmental potentia l of embryos produced from animals treated with r-hFSH alone or in com bination with r-hLH was evaluated. Embryos (n = 127) were cryopreserve d, thawed and either co-cultured on buffalo rat liver cells until the hatched blastocyst stage or transferred to synchronized recipients, Al though embryos from each treatment group demonstrated a similar abilit y to develop to hatched blastocysts with a definitive inner cell mass, a significant difference was seen in cryosurvival (56 versus 78%) and in developmental rate to the hatched blastocyst (12 versus 10 days) b etween embryos from the r-hFSH alone and the combination group respect ively, Pregnancies resulted following oviductal embryo transfers in bo th groups, with corpus luteum rescue occurring on days 12-16 of the lu teal phase, In summary, r-hFSH alone during the pre-ovulatory interval is adequate for the gametogenic events required to produce embryos th at develop either in vitro or in vivo; however, exposure to r-hLH may improve embryo viability and the rate of development.