Reverse cholesterol transport is done by:
Ans. c (HDL). (Ref. Harper, Biochemistry, 25th/pg.270)LIPOPROTEINFUNCTIONSChylomicron- Delivers dietary triglycerides to peripheral tissues and dietary cholesterol to liver.- Secreted by intestinal epithelial cells.- Levels are classically increased in lipoprotein lipase deficiency.0- Excess causes pancreatitis, lipemia retinalis, and eruptive xanthomas.VLDL- Delivers hepatic triglycerides to peripheral tissues.- Secreted by liver.- Excess causes pancreatitis.LDL- Delivers hepatic cholesterol to peripheral tissues.- Formed by lipoprotein lipase modification of VLDL in the peripheral tissue.- Taken up by target cells via receptor-mediated endocytosis.- Classically increased in familial hypercholesterolemia.- Most atherogenic.0HDL- So called 'good cholesterol'(anti-atherogenic).- Mediates centripetal transport of cholesterol (reverse cholesterol transport).- Acts as a precursor for apoC and apoE (which are needed for chylomicron and VLDL metabolism).- Secreted from both liver and intestine. # Lowest density lipoprotein with largest size>> Chylomicrons.# Highest cholesterol containing lipoprotein (50%)>> LDL.# Least cholesterol containing lipoprotein (5%)>> Chylomicrons.# Highest triacyglycerol containing lipoprotein>> Chylomicromins.# Highest protein containing lipoprotein>> HDL (2) albumin FFA (1).# Least protein containing lipoprotein>> Chylomicrons.# Least triacyl glycerol containing lipoprotein (3%)>> HDL.# Highest phospholipid containing lipoprotein>> HDL.# Exogeous lipid transport from intestine to liver & extrahepatic tissues through>> Chylomicrons.# Endogeous lipid transport is from liver to extrahepatic tissues via>> VLDL.# Reverse cholesterol transport is from extrahepatic tissues to liver via>> HDL.# Essential fatty acids are arachidonic acid.>> Linoleic acid, lenolenic acid &# Fatty acid chain with ?1 double bonds are unsaturated fatty acids, e.g., linoleic acid--18:2, lenolenic acid--18:3, arachidonic acid--20:4.e>> Oleic acid,
VLDL
LDL
HDL
Chylomicrons
Lipids