Flashcards in Lipids Deck (29)
Where does fatty acid synthesis take place? WHich special shuttle is required?
cytoplasm of hepatocytes
citrate shuttle (sytrate, synthesis)
Where does fatty acid degradation take place? Which special shuttle is required?
in the mitochondrial matrix
transferred via carnitine shuttle (carnage of fatty acids)
What does fatty acid synthesis begin with? Rate limiting enzyme?
begins with acetyl coa
uses acetyl coa carboxylase
What are the basic important things about fatty acid degradation?
**happens in mitochondrial matrix
**beta oxidation-->acyl CoA-->TCA or ketone bodies
Rate limiting enzyme: carnitine acyltransferase 1 or carnitine palmitoyltransferase 1
What does cholesterol synthesis begin with ?
In what way do statins inhibit HMG coa reductase?
What does Apo E do? Which things is it found on?
mediates remnant uptake
everything except LDL
What does ApoA-1 do Which things is it found on?
What does Apo CII do? What is it found on?
lipoprotein lipase cofactor
Chylomicron, VLDL, HDL
What does ApoB48 do? What is it found on?
ticket out of the intestine for the chylomicrons
found on chylomicron and chlymicron remnant
What does ApoB100 do? What is it found on?
binds LDL receptors, ticket out of liver
VLDL, IDL, LDL
What's the deal with chylomicrons?
secreted by intestinal epithelial cells (ApoB48)
take TGs to peripheral tissues
remnant takes cholesterol to liver
What's the deal with VLDL?
secreted by the liver (ApoB100)
delivers TG to peripheral tissue
What's the deal with IDL?
formed after degradation of VLDL
takes TGs and cholesterol to liver
What's the deal with LDL?
takes hepatic cholesterol to peripheral tissues
What's the deal with HDL?
has APOA1, lots of protein at first (nascent)
takes cholesterol from periphery to liver
What is Type I hyperchylomicronemia?
lipoprotein lipase deficiency or altered ApoCII
increased TG, chylomicrons, cholesterol.
Get pancreatitis, hepatosplenomegaly, xanthomas
No increased risk for atherosclerosis
What is Type IIa familial hypercholesterolemia?
absent or defective LDL receptors. Usu only see heterozygotes.
increased LDL and cholesterol
accelerated atherosclerosis, MI before age 20
What is Type IV hypertriglyceridemia?
hepatic overproduction of VLDL
super high triglycerides-->acute pancreatitis
high VLDL, TG
What is arcus senilis?
corneal arcus due to old age, lipid deposits in cornea
What do you call lipid deposition on eyelids?
Where is the lipid aggregating w/ xanthomas?
in the histiocytes of skin (dendritic cells)
What is abetalipoproteinemia?
autosomal recessive defect where you can't make Apo Bs,
decreased ApoB48 and ApoB100
therefore, decreased chylomicron and VLDL synthesis
Which gene is mutated in abetalipoproteinemia?
MTP gene (microsomal transfer protein)
How does abetalipoproteinemia present?
steatorrhea in first few months of life
impaired absorption of ADEK
impaired absorption of A-->night blindness, ataxia
What do you see on intestinal biopsy of patients with abetalipoproteinemia?
see enterocytes swollen w/ TG
What do you see on peripheral smear of patients with abetalipoproteinemia?
acanthocytosis of peripheral RBCs
b/c of lack of lipids, get spiky membranes.
What is the treatment for abetalipoproteinemia?