Flashcards in Lipoprotein Physiology Deck (26):
Describe the makeup of lipoprotein.
There is an apolipoprotein scaffold that holds cholesterol and triglycerides in the middle and has a phospholipid layer on the outside.
List the types of lipoproteins from biggest to smallest.
List the ratio of triglyceride to ester in each of the lipoproteins.
Chylomicrons (10:1 triglycerides to cholesterol)
Remnant IDL (1:1)
What are the types of lipoprotein found in each lipoprotein?
Remnant IDL: B? (not known)
LDL: B100 (because it is a downstream metabolite of VLDL)
Dietary fats are absorbed as ____________ and then __________.
broken up fatty acids (from lipase acting on triglycerides); get re-converted to triglycerides
The purpose of chylomicrons is to _______________.
deliver dietary fats to peripheral tissues
Liver makes fat and packages it as _________.
VLDL serves to _____________.
deliver liver-made fat to peripheral tissues
_____________ hydrolyzes VLDL triglycerides and leaves LDL.
Lipoprotein lipase (in the capillary bed)
LDL serves to _________________.
bring the unused triglycerides and cholesterol from VLDL back to the liver
You can count how many __________ particles there are by counting B100.
VLDL and LDL
Which part of the LDL molecule binds to hepatocytes?
How do statins decrease LDL?
They inhibit synthesis of hepatocyte cholesterol, causing the liver to get rid of more circulating LDL.
The liver secretes ______ which picks up peripheral cholesterol and brings it back to the liver.
nascent disks (which is basically A1)
What protein moves peripheral cholesterol to A1?
ABC A1 (adenosine-binding cassette A1)
If you lack ______, you'll have low circulating HDL due to inability to transfer peripheral cholesterol to HDL. This is a disease called Tangier's and presents with orange tonsils and many peripheral cholesterol plaques.
What does LCAT do?
Lecithin cholesterol acyl transferase transfers a fatty acid from a phospholipid to circulating cholesterol in HDL, creating cholesterol ester that is less soluble and therefore more likely to stick with the HDL particle on its route back to the liver.
Cholesterol ester transfer protein swaps some _________ for ____________ when triglyceride levels are high. Low levels of this protein have been associated with high levels of HDL and decreased CVD events.
cholesterol ester from HDLs; triglycerides from VLDLs
CETP results in the more rapid excretion of ________.
HDL, because triglyceride-laden HDL is more quickly excreted
Apolipoproteins can also be enzymatic cofactors, such as ___________.
C2 (for lipoprotein lipase)
Apolipoprotein E is a ligand for the __________ receptor.
True or false: cholesterol must undergo additional phase I metabolism to be excreted renally.
False. Cholesterol has to be excreted in the bile as is.
High triglyceride levels has been shown to cause ____________.
Dietary fats are broken down in the intestine by __________ before being absorbed by the intestinal villi and packaged into chylomicrons.
Why is it important to have people fast before measuring LDL and triglycerides?
Because dietary fat enters as chylomicrons and can skew the lab findings