LPL and metabolic syndrome: To test if impaired lipolysis of triglyceride-rich lipoproteins (TRLs, VLDL, chylomicrons, and their remnants) also might contribute to the postprandial dyslipidemia, we measured the mobilization and activity of lipoprotein lipase (LPL) after intravenous injection of heparin, which releases tissue LPL into the plasma.