Term
Chylomicron
Source?
Function & Route?
Apoproteins associated with it?
excess causes what? |
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Definition
secreted by intestinal epithelial cells
Delivers dietary triglycerides to peripheral tissues
delivers cholesterol in form of chylomicron remnants to liver
B-48, A-IV, C-II, E
pancreatitis, lipemia retinalis, eruptive xanthomas |
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Term
VLDL
Source?
Function & Route?
Apoproteins associated with it?
excess causes what?
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Definition
secreted by the liver
Delivers hepatic triglycerides to peripheral tissues
B-100, C-II, E
excess - pancreatitis |
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Term
IDL
how is it formed?
Function & Route?
Apoproteins associated with it?
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Definition
Formed in the degradation of VLDL
delivers triglycerides & cholesterol to liver (where they are degraded to LDL)
B-100, E
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Term
LDL
Source?
Function & Route?
Apoproteins associated with it?
excess causes what?
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Definition
Formed by hepatic lipase modification of IDL in the peripheral tissue.
Delivers Hepatic cholesterol to peripheral tissues or liver
B-100
excess - atherosclerosis, xanthoma, arcus corneae |
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Term
HDL
Source?
Function & Route?
Apoproteins associated with it?
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Definition
secreted from both the liver & intestine
t/p cholesterol from periphery to the liver
also acts as a repository for ApoC & ApoE
CETP, A-1
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Term
Apoprotein A-I or A-1
function?
structure of what? |
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Definition
Activates LCAT
major structural protein of HDL |
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Term
Apoprotein B-48
function?
what other Apo is it like, what difference? |
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Definition
mediates chylomicron secretion
derived from B-100
lacks LDL receptor of B-100 |
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Term
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Definition
binds to LDL receptor
mediates VLDL secretion |
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Term
Apoprotein C-II
function? |
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Definition
cofactor/activates for lipoprotein lipase
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Term
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Definition
| mediates Extra (chylomicron remnant) uptake |
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Term
Apoprotein (a)
shape?
function?
problems associated with it? |
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Definition
very large, resembles LDL particle
forms a complex with LDL
highly atherosclerotic |
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Term
| describe chylomicron metabolism |
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Definition
1. it exits the intestines into the blood with only the B-48 Apo attached.
2. HDL then donates C-II and Apo E to it.
3. LPL (lipoprotein lipase on adipocytes) hydrolyzes fatty acids from the chylomicron into adipose tissue
4. once it's cut up by LPL it goes to the liver and gets take up via the Apo E into the B/E receptor |
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Term
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Definition
VLDL exits the liver with ApoC attached
the LPL at the adipose tissue cuts it up & takes it's triglycerides thus converting the VLDL to IDL
the IDL can further lose triglycerides at the liver to become LDL (hepatic lipase)
now it can carry cholesterol to the liver through the blood |
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Term
| what is the reverse cholesterol pathway? |
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Definition
| HDL (synthesized in liver/intestines) carry cholesterol from the periphery to the liver. It doesn't have the ApoE, thus it t/f it's contents to VLDL & IDL to get it to the liver |
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Term
| which lipoproteins are involved in the exogenous / endogenous pathways? |
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Definition
exo - chylomicrons
endo - VLDL, IDL, HDL, LDL
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Term
| what does pancreatic lipase do? |
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Definition
| degradation of triglycerides in small intestine |
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Term
| what does LPL (lipoprotein lipase) do? |
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Definition
| degradation of triglycerides circulating in chylomicrons and VLDLs |
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Term
| what does HL (hepatic lipase) do? |
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Definition
| degradation of triglycerides remaining in IDL |
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Term
| what does LCAT (lecithin-cholesterol acyltransferase) do? |
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Definition
| catalyzes esterification of cholesterol |
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Term
| what does CETP (cholester ester transfer protein) do? |
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Definition
| transfer cholesterol esters to other lipoprotein particles |
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Term
what are two ways of getting cholesterol stored up in the cell?
what enhances / inhibits it? |
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Definition
through HMG-CoA reductase synthesizing cholesterol.
or through LDL & T3 uptake (thyroid hormone needed also)
enhance: insulin, ESREBP
inhibit: glucagon, cortisol, statins
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Term
| what's the healthiest state to be in regarding HDL & LDL levels? |
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Definition
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Term
| How are LDL foam cells formed? |
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Definition
LDL get's oxidized it doesn't go through the normal metabolism pathway.
instead macrophages engulf them
thus the macrophages become foam cells |
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Term
what two things induce HDL synthesis?
what about LDL? |
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Definition
HDL - exercise & regular alcohol consumption
LDL - weight gain, trans fats, diabetes, hypothyroidism |
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Term
hyperlipoproteinemias
type I - hyperchylomicronemia
what's increased?
due to what two causes?
symptoms?
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Definition
increased chylomicrons
elevated blood level of triglycerides & cholesterol
caused by lipoprotein lipase dificiency
or altered Apo C-II
Epigastric pain, turbid retinal vessels |
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Term
hyperlipoproteinemia
Type II - hypercholesterolemia
increased levels of what?
cause?
symptoms? |
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Definition
Increased LDL
Elevated blood levels of cholesterol
due to reduced LDL clearance cuz of reduced amt of LDL receptors
symptoms: CAD/plaques |
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Term
hyperlipoproteinemia
type IV - hypertriglyceridemia
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Definition
increased VLDL
elevated blood triglycerides
caused by hepatic VLDL overproduction |
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Term
Wolman Disease
cause?
what is at high levels in the blood?
symptoms? |
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Definition
defect in lysosomal cholesterol ester hydrolase
affects LDL metabolism
reduced LDL clearance - high LDL levels
symptoms: CAD/plaques |
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Term
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Definition
prevents breakdown of VLDL in liver thus less LDL secreted to the blood stream
result in more HDL formation |
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