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41 Cards in this Set
- Front
- Back
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What lipoprotein transports exogenous triglycerides?
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Chylomicrons
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What is the composition of chylomicrons (inside)?
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cholesterol
triglycerides |
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What are the apolipoproteins on chylomicrons that come from the gut?
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A
B-48 |
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What are the apolipoproteins on chylomicrons that come from HDL?
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C
E |
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How dense are chylomicrons compared to other lipoproteins?
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not very
(<0.95g/ml) |
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What happens to the TAG in chylomicrons?
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It is removed by lipoprotein lipase (LPL) in the peripheral tissues for storage/energy source.
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What happens to the cholesterol in chylomicrons?
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It is taken up by HDL, esterified, then exchanged for TAGs through cholesterol esterase transfer protein (CETP).
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What lipoprotein is for transporting endogenous triglycerides?
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VLDL
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Where does VLDL come from?
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the liver
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What does VLDL carry?
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triglycerides (TAG)
cholesterol phospholipids |
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What are the apolipoproteins on VLDL?
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B-100
C E |
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What is the density of VLDL compared to other lipoproteins?
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second lowest density
(0.96-1.006 g/ml) |
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What happens to the TAG from VLDL?
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It is taken up by peripheral tissues by LPL (similar to chylomicrons).
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What happens to the phospholipids/cholesterol from VLDL?
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As they become smaller, these are transferred to HDLs.
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What is IDL?
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Intermediate density lipoproteins:
(late VLDL lipoproteins who have lost some TAG, phospholipids, apolipoproteins) |
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What are the components of IDL?
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Same as VLDL, minus some:
TAG, phospholipid, cholesterol Plus some cholesterol esters ffrom HDL |
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What are the apolipoproteins of IDL?
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B-100
some C some E |
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What is the density of IDL?
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in between VLDL and LDL
(~1.007-1.019 g/ml) |
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What happens to the TAG from IDLs?
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It is transferred to HDL in exchange for cholesterol esters (through CETP)
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What happens to the rest of the TAG?
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It is removed by hepatic lipase.
This turns the IDL into LDL |
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Do some IDLs get taken up into the liver before turning into LDLs?
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yes
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What is the role of LDL?
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Transport of cholesterol
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What does LDL contain?
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cholesterol esters
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What are the apolipoproteins on LDL?
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B-100
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What is the density of LDLs?
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just under HDL:
(1.02-1.063 g/ml) |
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What happens to LDLs?
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- they pass through endothelial cell junctions
- attach to apoB100 receptors - get internalized and degraded by lysosomes - release free cholesterol |
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Where does HDL originate?
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the liver
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How does HDL start to form?
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with apolipoprotein AI and phospholipids it forms a nascent discoid
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How does nascent HDL mature?
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it gathers free cholesterol from the tissues (through ABCA1 transporter)
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Where does HDL get its apolipoproteins?
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A - liver, other lipoproteins/tissues
E - liver C -other lipoproteins/tissues |
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What are the contents of HDL?
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phospholipids
cholesterol |
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What is the role of HDL?
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1. reverse cholesterol transport
2. source of apoproteins for chylomicrons & VLDL |
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How is the free cholesterol taken up by HDL esterified?
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through lecithin cholesterol acyltransferase (LCAT)
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What happens to the cholesterol esters in HDL?
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They are transferred to CM remnants and IDL in exchange for TAG (through CETP)
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What happens to TAG that is taken up by HDL?
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It is taken up by the liver and excreted in bile
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What is the density of HDL?
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it is the highest:
1.064-1.21 |
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What is Lp(a)?
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a lipoprotein like all the others...
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What is the role of Lp(a)?
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unknown
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What is a high amount of Lp(a) a risk factor for?
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CHD
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What is the composition/density of Lp(a)?
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similar composition to LDL
larger & more dense than LDL |
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What are the apolipoproteins on Lp(a)?
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B-100
a |
