Plasma VEGF levels in neonatal rap1b^−/− mice are not decreased. VEGF levels in blood plasma collected from 6- to 8-day-old wild-type (■) and Rap1b^−/− mice (▧) were measured fluorescently using the Bio-Plex Mouse VEGF assay. Plotted is the average value; error bars are SEM (n = 3-7 mice per condition, samples assayed in duplicate). There is a significant elevation of VEGF levels in Rap1b^−/− mice at day 6 compared with the wild-type mice (P = .09).