A PRELIMINARY TRIAL OF HUMAN ZYGOTE CULTURE IN HAM F-10 WITHOUT HYPOXANTHINE

Purpose: This study deals with the suitability of Ham's F-10 without h ypoxanthine for early cleavage-stage embryo culture. A high percentage of mouse two-cell embryos developed into morula and blastocysts in Ha m's F-10 formulated without hypoxanthine (75.3 and 71.6%, respectively ); in contrast, in agreement with previous reports, only 15.4% develop ed beyond the two-cell stage in Ham's F-10 with hypoxanthine. To begin to evaluate the effect of hypoxanthine on human embryos, a total of 3 18 human oocytes was fertilized and cultured in Ham's F-10 minus hypox anthine. Results: The fertilization, cleavage, and pregnancy percentag es in two ovulation induction protocols [human menopausal gonadotropin (hMG)/human chorionic gonadotropin (hCG) and gonadotropin releasing h ormone/hMG/hCG] were 82, 88, and 20 and 83, 91, and 30%, respectively. Conclusion: These results suggest that, in agreement with mouse embry o development, hypoxanthine does not appear to be necessary for human embryo cleavage and its omission from Ham's F-10 may enhance the condi tions for culture of early-cleaving human embryos. These observations may lead to a better understanding of critical cell processes during e arly human embryonic development.