HYDROGEN-PEROXIDE STIMULATES ENDOCYTOSIS IN CULTURED BOVINE AORTIC ENDOTHELIAL-CELLS

Fluid-phase uptake of macromolecules by cultured bovine aortic endothe lial cells was measured using FITC-dextran (70000 Da). Low doses of hy drogen peroxide added extracellularly stimulated the uptake of macromo lecules by the endothelial cells. There was no general increase in the passive permeation or the transport across the cell layer. Moreover, when endothelial cells were stimulated with phorbol myristate acetate (PMA), macromolecules uptake was also enhanced. The PMA effect was blo cked with superoxide dismutase (SOD) and catalase, suggesting a pivota l role of oxygen metabolites in fluid phase uptake of macromolecules b y endothelial cells.