Inverse relationship between blood levels of high density lipoprotein subfraction 2 and magnitude of postprandial lipemia
Triglyceridemic response to a standard oral fat meal was determined in 28 healthy subjects and related to the levels of several lipids, lipoproteins, and apolipoproteins in the post-absorptive plasma. A fatty test meal was administered orally, and postprandial plasma triglyceride levels were determined. In the fasting blood samples, concentrations of apolipoproteins (apo) A-I, A-II, and B were determined by radioimmunoassay, and those of high density lipoprotein (HDL) subfractions HDL2 and HDL3, by zonal ultracentrifugation. The magnitude of triglyceridemic response showed a negative correlation with the plasma levels of HDL2 (r = -0.860, P less than 0.001), HDL-associated cholesterol (r = -0.605, P less than 0.001), and apoA-I (r = -0.459, P less than 0.02). No correlation was found between the triglyceridemic response and the levels of total cholesterol, HDL3, and apoA-II. Triglyceridemic response was correlated positively with fasting triglyceride concentrations (r = 0.450, P less than 0.02) and apoB levels (r = 0.396, P less than 0.03). In two subjects followed for 3 yr, when HDL2 levels rose or fell, the triglyceridemic response decreased or increased, respectively (r = -0.944; r = -0.863). Our data indicate that normolipidemic individuals with high HDL2 levels in the plasma are able to clear alimentary fat at a faster rate than normolipidemic subjects with low HDL2 levels. The pronounced difference in severity and duration of postprandial lipemia among subjects with varying HDL2 levels may help to explain the negative correlation between the risk of atherosclerosis and HDL cholesterol levels.