Summary
The effect of insulin on fibrinolysis was studied in hospital patients who were subjected to an insulin tolerance or glucose tolerance test. Blood samples were obtained at frequent intervals over a 2-3 hour period and fibrinolytic activity determined by the dilute whole blood lysis test. Normal control subjects were tested in both fasting and in non-fasting states. A marked increase in fibrinolytic activity was produced during the insulin tolerance test. However, as this increase did not appear until the blood glucose had been reduced to 30-40 mg % it was considered to be due, not to the insulin which had been administered, but rather to the action of those hormones which would be released in response to the hypoglycemia. On the other hand, the results of the glucose tolerance test demonstrated a gradual increase in fibrinolysis during the test period. Again this increased activity could not be attributed to the action of insulin because a similar effect was apparent in the samples obtained from the control subjects. Therefore, it was concluded that the enhancement of fibrinolysis observed in both test and control subjects was not due to the action of insulin.
