Relationship between Post-Heparin Plasma Lipases, Triglycerides and High Density Lipoproteins in Normal Subjects

The relationship between plasma lipids and lipoproteins and the lipolytic activities of post-heparin plasma lipoprotein lipase (LpL) and hepatic-triglyceride lipase (H-TGL) was examined in normal subjects. Seven males and six females were given a high fat diet [15% carbohydrate (CARB), 65% fat, 20% protein] for 2 weeks followed by 4 weeks of a high CARB diet (65% CARB, 15% fat, 20% protein). Changes in plasma triglyceride concentrations associated with diet were negatively correlated with changes in HDL-C (r = -0.533, P less than 0.001) and the HDL subfraction HDL2b (r = -0.308, P less than 0.001). The activity of LpL in post-heparin plasma was positively correlated with changes in plasma HDL-C (r = 0.668, P less than 0.001) and HDL2b (r = 0.457, P less than 0.001), and negatively with plasma triglycerides (r = -0.546, P less than 0.001). Changes in H-TGL activity were negatively correlated with changes in HDL2b (r = -231, P less than 0.05) and positively correlated with HDL-C (r = 0.326, P less than 0.01). These results in normal subjects provide further evidence that LpL and H-TGL are important enzymes in the metabolism of plasma lipoproteins and that changes in their activities contribute to plasma lipid and lipoprotein concentrations.