endogenous fat pathway Flashcards
______ is a lipoprotein produced by the liver that provides the means for fats to be distributed throughout the body (endogenous pathway)
VLDL
VLDL are assembled in ____
hepatocytes
the core of VLDL contains ____ and ____ which were synthesized in the smooth ER or recovered from the uptake of other particles
cholesterol esters and triglycerides
the final assembly of the VLDL occurs in the _____
Golgi apparatus
Apo____ is inserted into the outer layer of VLDL to be an “address protein” that will ultimately be needed to recover the remnants of the particle
B100
Apo ___ is also inserted into VLDL and is needed as a catalyst for lipoprotein lipase attached to the blood facing side of capillary endothelial cells in adipose and muscle tissue
C
the VLDL is secreted from the liver into the _____ in a form called nascent
circulation
upon entry into the blood. the nascent VLDL will pick up additional Apo proteins from HDL, including more ____ and ____
Apo C and Apo E
VLDL comes in contact with _____ which is bound to the endothelial cells of capillaries in muscle and adipose tissue
lipoprotein lipase
in order to catalyze the lipoprotein lipase reaction, ____ is present in the outer layer of the VLDL particle
Apo C
lipoprotein lipase breaks down triglycerides into ___
free fatty acids
_____ is a particle formed from VLDL depleted of triglycerides
IDL (intermediate density lipoprotein)
IDL can be cleared up by the liver by ____
LDL receptors that recognize Apo B 100 and Apo E
half of the IDL are taken up by the liver and the other half are converted to ____
LDL (low density lipoprotein)
LDL accounts for about ____ of the total lipoprotein content of plasma
two thirds
LDL is derived from ____ that has delivered a large portion of its triglyceride content to the tissues
VLDL
human LDL particles contain __
cholesterol, proteins, phospholipids, triglycerides
why is LDL the main carrier of plasma cholesterol
cholesterol is concentrated by removal of triglycerides and there is a large amount of LDL in the circulation
when LDL levels are elevated above normal, there is good evidence that the development and progression of ______ is accelerated
atherosclerosis
it is well documented that LDL is a major component of _________
atherosclerotic plaques
LDL is said to be _____
proatherogenic
how is LDL cleared from the circulation
it binds to LDL receptors that recognize ApoB100 as a ligand
HDL is responsible for what is called _______
reverse cholesterol transport from tissues to liver
HDL particles are formed by the ____
liver
the first step in the formation of HDL is the synthesis of _____. the major protein associated with the HDL particle
apoA1
apoA1 is secreted from the liver in association with _____
phospholipids
once in the circulation, the new HDL particle begins to take up ______
free cholesterol
HDL contains the enzyme _____
lecithin-cholesterol acyltransferase (LCAT)
LCAT ______ the free cholesterol and the result moves to the core of the HDL
esterifies
the action of LCAT ensures that _____
concentrations of free cholesterol remain low (creates a concentration gradient for cholesterol to move into HDL)
HDL returns the cholesterol ester to the liver by two mechanisms which involve ______
cholesterol ester transfer protein (CETP)
what 2 ways can HDL return cholesterol to the liver
it can transfer cholesterol esters to VLDL/IDL/LDL that are taken up by hepatocytes, or HDL itself can dock with hepatocytes and transfer cholesterol
the removal of cholesterol from artery walls by reverse cholesterol transport is believed to account for the ________ effect of HDL–> this is why HDL is called good cholesterol
antiatherogenic
