Anti-hyperlipidemic drugs Physio- Duan Flashcards
What are lipoproteins?
protein-lipid complexes responsible for transport of plasma lipids
What are found on the surface of Lipoproteins?
- phospholipids
- unesterified cholesterol
- Apolipoproteins
What is the core of a lipoprotein made up of?
- Cholestery esters (CE)
- Triglycerides (TGs)
What are the lipids in lipoproteins?
TAGs
Phosopholipids
Cholesterol Cholesteryl esters
What Lipoproteins (LP) are greater than 30 nm?
-Chylomicrons, VLDL, and catabolic remnants
D <1.006 g/ml
What LPs are 20-22 nm in size?
LDL
D=1.019-1.063g/ml
What LPs are 9-15 nm in size?
9-15 nm
D=1.063-1.21 g/ml
Put the types of lipoproteins in order from LARGEST densitiy and SMALLEST diameter to least dense and largest diameter.
HDL>LDL>IDL>VLDL>Chylomicron
What are the 2 pathways for lipoprotein metabolism?
- Exogenous/chylomicron pathways (dietary fat i.e you eat it)
- Endogenous pathway (lipids synthesized by the liver)
How do package fats into chylomicrons?
Bile salts solubilize dietary TG-> TGs are hydrolyzed by pancreatic lipases-> diffuse into intestinal epithelial cells-> TGs re-synthesized in ER->packaged into chylomicrons
What is the composoition of a chylomicron?
What lipoproteins are associated with it?
What is the half life?
TG > 90% CE + cholesterol < 5% Phospholipids 5-10 % Protein 1-2 % Fat soluble vitamins
Apo A, B-48 initially
Apo E and Apo C’s
acquired in circulation
5-30 minutes
How do you breakdown TAGs in chylomicrons into FFA and glycerol and what happens to these?
Lipoprotein lipase is activated by Apo C-II on surface of capillaries of adipose and muscle tissue
- hydrolyzes TG to free fatty acis and glycerol
- FFA can be reused for energy or re-esterified
How do you go from a chylomicron to a chylomicron remnant?
- as chylomicrons lose their TAGs via LPL (activated by apo- CII) they shrink.
- Apo E and Apo C are transferred to HDL
- WHEN ALL APO C IS GONE you now have a chylomicron remanant with CE> TG
What happens to the chylomicron remnants?
Whats the half life of these?
Since they have lose Apo C-II, LPL is no longer activated and the remnants are taken up by liver
-about 5 minutes
Explain the exogenous/chylomicron pathway of metabolism
Step 1: Bile salts solubilize dietary TGs and hydrolyzed by pancreatic lipases-> go into intestinal -> TGs re-synthesized in ER->packaged into chylomicrons
Step 2: LPL activated by ApoC-II breaks down TAG into glycerol and FFA.
Step 3: chylomicrons become remnants via loss of all APO C and get taken up by liver
(blank) is responsible for endogenous TG formation and transport
VLDL
What is the composition of VLDL?
(smaller than chylomicrons) Surface Monolayer - Phospholipids (12%) - Free Cholesterol (14%) - Protein (4%) Hydrophobic Core - Triglyceride (65%) - Cholesteryl Esters (8%) - C 8-10 %, CE 12-15 %