Figure 5

VEGF mRNA (open squares) relative to β-actin levels in trilaminar yolk sac during the final third of gestation (A) or in vitro (B). VEGF expression in the trilaminar yolk sac was examined at stages 19–21 (n = 8), 22–24 (n = 7), and 25–26 (n = 6). A gradual increase in VEGF expression is evident and by term (days 25–26) expression was significantly higher than days 19–21 (t-test, one-way, equal variance, P= 0.002, F-test = 0.165). Trilaminar yolk sac explants were cultured for 8 (n = 4) and 18 (n = 5) hours with hr-IGF2 (treatment: stippled bars) or in media only (control: open bars). VEGF expression was consistently higher in IGF2 treated explants (see text).