Fig. 1.

Vascular endothelial growth factor knockout (VKO) mice have decreased liver vascular endothelial growth factor (VEGF) protein during embryonic and adult time points. VEGF protein levels in liver (A and B) and serum (C and D) were analyzed by ELISA in embryonic and postnatal control and VKO genotypes. Measurements were performed in duplicate and standardized relative to total liver protein (A) or total serum volume (C). A: each square or circle represents one biological sample. In controls, liver VEGF levels were highest at embryonic day (E) 16.5 and decreased progressively over time. At E16.5, postnatal day (P) 3, P15, and P30, VKO mice have significantly less VEGF protein in the liver than littermate controls. No compensation for the loss of liver VEGF was observed in the serum. There was no significant difference in serum VEGF levels between control and VKO mice at P3 or P15. However, at P30, VKO mice display a significant reduction in serum VEGF compared with controls. The average VEGF protein concentrations in liver tissue (B) and serum (D) are provided for control and VKO mice at all time points. The percentage reduction in relative VEGF protein levels between controls and VKO is shown for all time points. *P < 0.05, **P < 0.01, and ***P ≤ 0.001.