Lipids Flashcards
Cholesterol is a steroidal compound with C___
27
What enzyme is cholsterol synthesized from
acetyl coenzyme A
How does HMG CoA go to Mevalonic Acid
by HMG CoA reductase
What molecules are triglycerides formed from
glycerol-3-phosphate
What are the 4 classifications of major plasma lipoproteins
very low density lipoproteins
intermediate-density lipoproteins
low-density lipoproteins
high-density lipoproteins
Statins are inhibitors of HMG-CoA reductase and they lower plasma cholesterol levels by what three mechanisms
inhibition of cholesterol biosynthesis
enhancement of receptor-mediated LDL uptake
reduction of VLDL precursors
What is the pharmacophore of HMG-CoA reductase inhibitors
7 ring system dihydroxyheptanoic acid
The decalin ring is essential for anchoring the drug to the enzyme _______ _____
active site
Does a beta hydroxyl group increase or decrease hydrophilicity
increase (may improve cellular specificity)
What statin is the most hydrophilic and therefore has minimal penetration into lipophilic membrances, better selectivity for hepatic tissues and reduction in side effects
Pravastatin
All HMGRIs in active form contain a carboxylic acid that is primarily ________ at physiological pH
ionized
What CYP enzyme metabolizes HMGRIs
CYP34A
When should statins be administered
at night because it counteracts the peak cholesterol synthesis that occurs in the morning
Cholesterol Absorption Inhibitor MOA (ezetimbie)
-inhibits the absorption of cholesterol at the brush border of the small intestine
-competitively binds to sterol transporter
Ezetimibe is selective and does not interfere with the absorption of what molecules
triglycerides
lipid soluble vitamines
In Cholesterol Absorption Inhibitors the hydrolysis or expansion of the beta-lactam ring produces an ________ compound
inactive
Why is the secondary alcohol of ezetimibe not as important as the phenolic alcohol
The drug can conjugate to become active at the phenolic site
Bile Acid Sequestrants act by what MOA
binding to major bile acids, glycocholic acid and taurocholic acid, and greatly increase their fecal excretion
Bile acid sequestrants do not bind to specific receptors but bind to _______ charged atoms or functional groups on drug molecules
negatively
Since bile salts contain numerous positive charges they are more likely to bind to ________ compounds or nonelectrolytes
acidic
Impaired lipolysis by nicotinic acid ________ the mobilization of free fatty acids which reduce their plasma levels and their delivery to the liver
decreases
Nicotinic acid does not have any effects on what two things
cholesterol catabolism or biosynthesis
Fibrate MOA
-decrease plasma triglyceride levels more than cholesterol levels
-help lipoprotein metabolism by activation of peroxisome proliferator-activated receptors (alpha)
Which group in fibrates are essential for activity
isobutyric acid and the phenoxy ring
The extra space in gemfibrozil enhances _____ solubility which allows the drug to be absorbed through the GI membrane without the need of an ester prodrug
lipid
What functional group is important for fibrate binding and activity
carboxylic acid
Fenofibrate is a ______ that undergoes rapid hydrolysis to produce fenofibric acid active metabolite
prodrug
Dyslipidemia
Levels of lipids or lipoproteins in the blood that are outside or normal boundaries and have adverse effects
Hyperlipidemia
elevated levels of lipids or lipoproteins in the blood (mainly family)
Hyperlipidemia and ASCVD are associated with a general inflammatory state that contribute to ___________________ disorders
neurodegenerative
Primary risk factors of hyperlipidemia
reduce clearance that cause overproduction of LDLs or triglycerides
increase clearance that cause underproduction of HDLs
Secondary risk factors of hyperlipidemia
diet
sedentary life
obesity
diabetes
excessive alcohol
CKD
hypothroidism
liver dieases
Risk factors of low HDL
SMOKING
anabolic steroid use
HIV infection
nephrotic syndrome
What are chylomicrons synthesized from
synthesized from dietary triglycerides, cholesterol, and lipid-soluble vitamins in small intestine
Synthesized intestinal cholesterol and plant sterol absorption by what
niemann-pick c1-like protein 1 (NPC1L1)
ATP-binding cassette transporters pump what back into intestinal lumen
plant sterols
What is diagylcerol transferase transferred by
microsomal triglyceride transfer protein (MTP) to newly forming chylomicrons
What is ApoB-48
organizes newly forming chylomicrons
Type 2 isozyme of acyl-coenzyme A; __________ _________ esterifies dietary cholesterol, regulates cholesterol absorption
cholesterol acyltransferase (ACAT2)
________ enter the lymphatic system, pass to circulation via thoracic duct
chylomicrons
Chylomicronemia syndrome is genetic impairment of _____ or _______, impair chylomicron function
LPL
apoC-II
(cause severe hypertriglyceridemia, pancreatitis)
Chylomicron remanants are remanants after __________ from chylomicrons
triglycerides
What are the different chylomicron remanants
endothelial fenestres
ApoE
Hepatic lipase (HL)
LDL receptor or LDL receptor-related protein
What is LDL
-produced in liver, large, can cause plasma turbidity
-production is stimulated by triglycerides released from chylomicrons
What is IDL
triglycerides in VLDL metabolized by LPL to form IDL
released from capillary beds into circulation
How is LDL cleared
ApoB100/LDL receptor interaction in hepatocytes
Atherosclerosis is a syndrome in which atherosclerotic _________ develop in arteries, producing narrowing of the arterial passage and thickening of the arterial wall
plaques
How are plaques formed in atherosclerosis
oxidized LDL is taken up by macrophages
HDL is produced by liver and intestine and form chylomicron ___________ and VLDL
remnants
Pre-beta1 HDL primarily mediates transport of __________ to and from other cells
cholesterol
Lecithin is cholesterol acetyltransferase that esterifies cholesterol in what
pre beta1 HDL
HDL
HDL2
HDL3
In reverse cholesterol transport ____ absorb cholesterol from peripheral cells/macrophages
HDL
HDL2 and HDL1 exchanges cholesterol in liver excreted in bile _____ with bile _______
ducts
salts
In exogenous lipid transport ____ hydrolyzes triglycerides; free fatty acids absorbed by tissues
LPL
In exogenous lipid transport LPL releases free fatty acids to form _____
IDL
Cholesterol synthesis: long metabolic pathway, begins with transport of _________ from mitochondrial stores
acetyl-coA
3-hydroxy-3-methylgutaryl-CoA synthesized from acetyl-CoA and acetoacetyl-CoA by what
HMG-CoA reductase
Drugs that treat hypercholesterolemia
statins
ezetimibe
bile acid-binding agents
PsK9 inhibitors
Drugs that treat hypertriglyceridemia
fibrates
omega-3 fatty acids
niacin
What is the rate limiting step in cholesterol synthesis
HMG-CoA reductase
Statin inhibit HMG-CoA reductase which reduce endogenous ________ _________
cholesterol synthesis
What are the two natural statins
mevastatin
lovastatin
What are the two synthetic statins
pravastatin
simvastatin
fluvastatin
atorvastatin
rosivastatin
pitavastatin
All statins contain a _______ acid side chain that is a structural analog of an HMG-CoA intermediate
heptanoic
Membrane-bound (sterol regulatory element bring protein) is cleaved by a protease and SRE translocates to the ______
nucleus
SRE increases expression of ______ gene
LDLR
Statins increase the removal of LDL from the blood __________ LDL-C
lowering
Where are statins absorbed
small intestine
Where are statins distributed
most in liver
low levels in plasma
mostly protein-bound
How are statins metabolized/excreted
metabolized in liver and excreted in feces
What is rhabdomyolysis
toxic muscle protein products in serum
Carriers of PCSK9 cause a loss of function allele which _____ MI
decreases
Fibrates are what kind of agonist
peroxisome proliferator-activated receptor alpha (PPARalpha)
Fibrates reduce triglyceride levels by how much percent
30-50%
What are the two main fibrate drugs
gemfibrozil
fenofibrate
Omega 3 fatty acids are peroxisome proliferator-activated receptor _____ and ______
alpha
gamma
Cholesterol uptake inhibitor drug
ezetimibe (zetia)
Ezetimibe inhibit luminal cholesterol absorption via ________ by jejunal enterocytes
NPC1L1