FIG. 2.

Graph of embryo progression during 4 days in vitro. Fertilized eggs from mice treated neonatally with Gen (n = 15 mice [373 embryos]) or with corn oil alone (n = 11 mice [231 embryos]) were followed up for 4 days in culture to determine progression of development. A) The percentage of embryos that progressed to each stage was determined for each mouse, and the mean ± SE is plotted. The asterisk denotes statistical significance at P < 0.05 (Wilcoxon test). PN, pronuclear stage; 2C, two-cell stage; 4–8C, four- to eight-cell stage; Mor, morula stage; Blast, blastocyst stage. B) Percentage of embryos at the four-cell (4C) or five- to -eight-cell (5–8C) stage of development 48 h after hCG administration. Overall, 211 embryos from control mice and 356 embryos from Gen-treated mice were evaluated. There were significantly fewer five- to eight-cell embryos in the Gen-treated group than in the control group (P < 0.0001, Fisher exact test).