Lipoproteins are macromolecular complexes composed of lipids and proteins. They exist to transport hydrophobic lipids and proteins within the circulation. A key function of the apolipoprotein B-containing lipoproteins is the transport of energy in the form of esterified fatty acids (in triglycerides (TGs)) to tissues that utilize them or store them. Intestinally derived chylomicrons deliver dietary fat to the periphery, whereas liver-derived very low density lipoproteins (VLDL) deliver endogenous fat (fatty acids transported to liver from adipose or newly synthesized in liver) to the periphery. Lipolysis of TGs in the periphery is mediated by the key enzyme lipoprotein lipase (LPL). Low-density lipoproteins (LDL) are by-products of VLDL metabolism and are the major cholesterol-carrying lipoprotein in plasma. LDLs are taken up by the liver by the LDL receptor and other receptors. High-density lipoproteins (HDL) mediate the transport of cholesterol from the periphery back to the liver for excretion. Normal lipoprotein metabolism is essential for health, and a variety of inherited and acquired disorders disrupt normal lipoprotein metabolism and cause dyslipidemia and other consequences.
KeywordsLipoproteins Cholesterol Triglycerides LDL HDL Metabolism
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