Lipolytic Activity of Post-heparin Plasma in Hyperlipemia and Hypolipemia.

• The demonstration of a heparin-stimulated lipemia-clearing (lipolytic) factor in the plasma of animals and m a n w suggests that a deficiency of this factor may lead to the production of hyperglyceridemia in atheroscle-rotic patients. A number of investigators have compared the lipolytic activity of plasma from atherosclerotic patients and from normal individuals after giving them small doses of heparin intravenously. Some reported lower activities in the atherosclerotic patients; 5 " 7 others did not find a significant difference. 8 " 10 Much of this difference may be explained by: (1) lack of a standardized method for assaying post-heparin plasma lipolytic activity (PPLA), (2) failure to recognize the influences of dietary fat and calories upon the level of the plasma enzyme activity, and (3) failure to differentiate the clinical types of hyperlipidemia. The purposes of this study are (1) to define more accurately the relationship between PPLA and the production of hyperglyceride-mia, and (2) to determine the conditions that may alter the activity levels of plasma lipolytic enzyme in man. Methods GROUPS STUDIED (a) Normal Subjects This group consisted of 30 young, healthy normolipemic subjects with plasma triglyceride concentrations lower than 180 mg/100 ml, and included 20 males and 10 females, ranging from 19 to 28 years of age. These subjects were technicians, doctors, and medical students. All had been eating a normal American diet for many weeks prior to the study. Twenty-four hyperglyceridemic patients, including 18 males and 6 females, ranging from 4 to 62 years of age, were divided into two groups according to their clinical manifestations and to their responses to the fat and carbohydrate contents in the diet. 11 (1) Twenty-two Patients Having "Mixed" Hyper-glyceridemia. In these, both fat and carbohydrate calories contributed to the hyperglyceridemia. They showed variable responses to low fat diet initially but their serum triglyceride levels remained elevated on a high carbohydrate intake. It has been shown in these patients, with an expanded tri-glyceride pool of endogenously synthesized tri-glyceride, that the fractional removal rate of the absorbed food fats is decreased, with resulting accumulation in the blood stream. 12 This "mixed" hyperglyceridemia group included the "carbohy-drate-induced" hyperglyceridemia as described by Ahrens and his associates. 17 None of the patients had diabetes mellitus. All except four were known to have either coronary or peripheral arterial disease , or both. Ten of them had tuberous xan-thomata. Their turbid plasma did not separate,