Observations on in vitro and in vivo Agglutination of Platelets by “Bound” Insulin Concentrates. ∗

Summary

Data have been presented indicating that partially purified preparations of “bound” insulin have the ability to cause hemorrhage, thrombosis and non-coagulability of blood when injected intravenously into 48-hour-fasted rats. Similar injections into fed rats produced no apparent pathology. Heparin (0.1 mg) injected simultaneously with “bound” insulin concentrates into fasted animals prevented the occurrence of hemorrhage and thrombosis. Crystalline insulin (1 to 5 milliunits), injected in the same manner as heparin either partially or completely inhibited the production of hemorrhage and thrombosis in the fasted rats. It was also observed that “bound” insulin concentrates aggregated platelets in vitro. No platelets could be found in the uncoagulated blood from fasted rats injected intravenously with “bound” insulin. It is suggested that the vascular changes observed are related to platelet agglutination induced by “bound” insulin and the nutritional status of the animals.