Plasma Fibrinolysis in Man : T H E Effect

In 1955 Fearnley and Lackner (2) demonstrated the presence in human plasma of "spontaneous fibrinolysis. ''1 They reported that this activity was thermolabile, that dilution of the plasma increased its degree, and that either exogenous epinephrine or mild exercise resulted in increased activity (1, 2). A previous study from this laboratory reported significant inhibition of such fibrinolysis after ingestion of liquid meals containing large amounts of butterfat (3). These observations were in agreement with the data of Greig which showed that ingestion of meals containing certain mixed animal fats inhibited fibrinolysis (4). Subsequent reports by Nitzberg and coworkers (5), Billimoria and coworkers (6), and Buckell and Elliott (7) supported these conclusions. Although our observations were restricted to a single dietary fat, the results indicated that the chylomicrons of human plasma were solely responsible for the observed inhibition. The purposes of the present study were to quantify more completely the observations of our initial study, to observe the effects of two additional natural fats on plasma clot lysis using a modification of our original system, and to examine the fatty acid composition of the dietary fats and of the chylomierons that appear in the blood stream after ingestion of these fats. The dietary lipids used (butterfat, egg yolk, and safttower oil) were distinctly different in fat ty acid composition and in many other respects, including iodine number (40, 76, 141), sterol (2.8, 4.0, 0.2 per cent), and phospholipid (11, 26, <0.1 per cent), and served as representative samples of commonly ingested fats. In addition, their great divergence in composition allowed a broader test of the possibility