Vascular permeability-increasing action of hypoalbuminemic substance from Ehrlich ascites carcinoma cells.

A hypoalbuminemic substance (F-3), which was obtained from Ehrlich ascites carcinoma cells, showed a marked vascular permeability-increasing action in mice. The highest increasing effect was produced 20 min after an intradermal injection of F-3. This action was inhibited by diisopropyl fluorophosphate, soybean trypsin inhibitor, and indomethacin but not by hydrocortisone or D-2-bromolysergic acid diethylamide. The inhibition of F-3 by diisopropyl fluorophosphate was observed in partial even after the excess diisopropyl fluorophosphate was removed from the diisopropyl fluorophosphate-treated F-3. The hypoalbuminemic and hypoproteinemic actions were not subjected to any inhibition by the diisopropyl fluorophosphate treatment. The decrease in albumin produced 3 hr after the injection of F-3 would be due to the leakage of albumin from blood vessels. F-3 might contain at least two components, one being a vascular permeability-increasing substance and the other a hypoalbuminemic one.