Synergism of vitamins A and C on fibrinolysis

A hitherto unknown synergism exerted by retinol (vitamin A) and L-ascorbic acid (vitamin C) was discovered using endothelial cells. Retinol stimulated the extracellular and intracellular activities of plasminogen activator up to approximately 8- and 4-fold from the control values, respectively. L-Ascorbic acid enhanced the extracellular and intracellular activities up to approximately 1.5-fold. Above all it was demonstrated that their effects on extracellular activity were synergistic; simultaneous administration of these two vitamins enhanced the extracellular activity up to a 20- to 50-fold. Synthesis of plasminogen activator induced with vitamins A and C was inhibited by a protein synthesis inhibitor, cycloheximide.