VASCULAR ENDOTHELIAL GROWTH-FACTOR UP-REGULATES CONSTITUTIVE CYCLOOXYGENASE-1 IN PRIMARY BOVINE AND HUMAN ENDOTHELIAL-CELLS

The effect of the angiogenic cytokine vascular endothelial growth fact or (VEGF) on nitric oxide synthase (NOS) and cyclooxygenase (COX) expr ession was examined in human (HUVEC) and bovine (BAE) endothelial cell s. VEGF (10 ng/ml) induced constitutive COX-1 expression in both HUVEC and BAE, but not the cytokine-inducible isoform, COX-2, inducible NOS or endothelial NOS. In HUVEC, VEGF(10 ng/ml) increased COX activity, but COX inhibitors had no effect on the proliferative response of endo thelial cells to this cytokine. In conclusion the induction of COX-1 b y VEGF is not involved in the mitogenic response of endothelial cells, but may be an important regulatory mechanism in the maintenance of va scular integrity.