Which of the following is quantitatively the major contributor to routine clinical measurements of circulating plasma cholesterol concentrations?
LDLs are the primary carriers of blood cholesterol. Routine plasma lipid measurements are carried out after a 12-hr fast. In this way, the major endogenous plasma lipoproteins, VLDLs, and the major exogenous plasma lipoproteins (chylomicrons) have been cleared from the blood of normal individuals. LDLs, which are the end products of VLDL delipidation, and HDLs, which are protein rich, are the only lipoproteins circulating after a 12-hour fast. LDLs are rich in cholesterol, being composed of about 45% cholesterol or cholesteryl esters. In both dietary and familial hypercholesterolemia, circulating LDL levels are increased. Ref: Grundy S.M., Smith, Jr S.C. (2011). Chapter 92. Metabolic Syndrome, Obesity, and Diet. In V. Fuster, R.A. Walsh, R.A. Harrington (Eds), Hurst's The Hea, 13e.
Chylomicrons
Low-density lipoproteins (LDLs)
High-density lipoproteins (HDLs)
Intermediate-density lipoproteins (IDLs)