Platelet activating factor modulates peptidoleukotriene effects on the permeability of bovine aortic endothelial cell to albumin.

The purpose of the present experiments was to study the potency of various inflammatory mediators to modulate the clearance rate of 125I-albumin through bovine aortic endothelial cell (BAEC) monolayer on polycarbonate micropore membrane. The incubation of BAEC with LTD4 (10(-8)-10(-6) M) increased dose-dependently the permeability to radioactive albumin. The effect was potentiated by addition of PAF (10(-5) M). LTC4 had a less potent action on the clearance rate of 125I-albumin, since only the highest dose of LTC4 used (10(-6) M) had a significant effect, and it was not potentiated by PAF (10(-5) M). The treatment with PAF alone at concentration up to 10(-5) M did not increase the 125I-albumin clearance rate. Our results suggest that BAEC may bear specific receptors for LTC4 and LTD4 or that LTC4 is not converted to LTD4 by BAEC. Our results also suggest that LTD4 could possibly stimulate the expression of PAF receptors on BAEC.