The Presence of VEGF Receptors on the Luminal Surface of Endothelial Cells Affects VEGF Distribution and VEGF Signaling
Figure 3
Free VEGF concentrations in tissue and blood as a function of the receptor density.
The secretion rate is fixed so that, at a vascular permeability of 4×10−8 cm/s, 1 pM of free VEGF is present in the plasma (no luminal receptors; 10,000 abluminal receptors of each species per endothelial cell). VEGF secretion rate is 0.2390 molecule/cell/s. The density of abluminal and luminal receptors was varied from 0 to 10,000 receptors per endothelial cell surface. Note that no steady state could be reached at such secretion rate in the absence of abluminal receptors. The free VEGF concentration in the available interstitial fluid was constant over the range of luminal receptor density and decreased exponentially with the density of abluminal receptors. The free VEGF concentration in the plasma was significantly changed when the density of receptors was low.