Edwards Lectures Flashcards
What is arachidonic acid synthesized from?
It is synthesized from fatty acids with lipases. It acts as a precusor for many signaling molecules (thromboxanes, prostaglandins)
What is cholesterol synthesized from, and what is it made into?
Made from Cholesterol esters (cholesterol esterase) and converted to steroid hormones (desmolase) and bile salts
What are the components fo bile salts
cholic acid & glycis
function of plasma lipoproteins (LPL)
transport lipids throughout the blood. Polar surface with proteins, and a very hydrophobic core, rich in TGs and CEs
What is the major compoenet of Chylomicons? VLDL? LDL? HDL?
Chylomicrons & VLDL= TGs; LDL: Cholesterol, HDL: low in bad stuff, protective
LDL & HDL relationship to CHD
LDL levels correlate strongly with CHD, HDL levels correlate inversely
Drug: Eztimibe
Blocks cholesterol absorption by enterocytes
Pancreatic lipase
TG to FA + Monoacyl glyceride
Cholesterol Esterase
Cholesterol ester to Cholesterol and FA
Trace the path of chylomicrons from the intesting
Chylomicrons: from small intestine to capillaries. LPL on adipose and muscle tissue, TG and FFA are delivered to these tissues–> Chylomicron remnants to the liver
LPL or ApoCII (Cofactor Deficency (mutation in eaither gene)
Causes Hyperchoomicronemia: xanthomata, pancreatitis, and death. Blood is very rich in CMs
How/why can type 1 diabetic exhibit hypertriglyceridemia/chylomicronemia?
LPL levels require insuline, thus LPL activity is reduced in the absence of insulin
What happens to fatty acids in muscle?
They undergo beta oxidation to generate ATP
What happens to FAs in adipose?
They are resynthesized into TGs for storage
Is the chylomicron remnant TG rich or TG poor
TG poor, LPL on muscle and fat, FFAs have been delivered to these tissues.
The liver takes up chylomicrons and converts them to this before sending them out…
VLDL, then VLDL is reabs or becomes LDL and is reabs.
VLDL is very cholestrol rich. it is hydrolized by LPL and converted to LDL. LDL is…
very cholesterol ester rich, and it provides cholesterol to cells, which is necessary from growth. LDL is cleared, majority is endocytosed by the LDLR on hepatocytes.
Statins: how do they work?
Partially inhibit HMG CoA reducatase, which converts acetate to cholesterol (inc acitivity when plasma glucose levels are high), thus there is a decrease intracelluar cholesterol, and this triggers increased transcription of the LDLR gene, so more LDL is cleared from the plasma and taken up int the liver
SREBP2?
It is the transcription factor for HMG CoA reducatase. It is activated when plasma cholesterol levels are low and inhibited when they are high. Thus, statins causing lowered plasma cholesterol also increases the activity of the SREBP2 transcription factor and syntehsis of LDLR. s
LDLR
Crucial in clearing LDL
Familiar hypercholesterolemia
defective LDLR, thus there is high cholesterols in the blood, more LDL is depositied into tissued –> early MI
High Cholesterol–> LDLR & HMGCR
High C–> low LDL R and HMGCA, Low C–> High LDLR, high HMGCR; thus regulated cholesterol levels.
T/F Statins must be taken for life or cholesterol levels will return to normal
true
Statins do not work for famliial hypercholesterolemia
because they do not have normally functionling LDLR, whcih is the main way that statins work, is by upregulating this transporter
When statins increase clearance of LDL to the liver, where does the extra cholesterol go?
it is released as bnile.
High Cholesterol–> LDLR & HMGCR
High C–> low LDL R and HMGCA, Low C–> High LDLR, high HMGCR; thus regulated cholesterol levels.
T/F Statins must be taken for life or cholesterol levels will return to normal
true
Statins do not work for famliial hypercholesterolemia
because they do not have normally functionling LDLR, whcih is the main way that statins work, is by upregulating this transporter
When statins increase clearance of LDL to the liver, where does the extra cholesterol go?
it is released as bnile.
What is arachidonic acid synthesized from?
It is synthesized from fatty acids with lipases. It acts as a precusor for many signaling molecules (thromboxanes, prostaglandins)
What is arachidonic acid synthesized from?
It is synthesized from fatty acids with lipases. It acts as a precusor for many signaling molecules (thromboxanes, prostaglandins)
