Metabolism V Flashcards
rate limiting step cholesterol synthesis
HMG CoA reductase
inhibited by statins
-competitive and reversible
insulin
induces HMG CoA reductase
pancreatic lipase
degration of dietary TGs in small intestine
lipoprotein lipase
degradation of TGs circulating in chylomicrons and VLDLs
found on vascular endothelial surface
hepatic TG lipase
degradation of TGs remaining in IDL
hormone sensitive lipase
degradation of TGs stored in adipocytes
LCAT
esterification of cholesterol
cholesterol ester transfer protein (CETP)
mediate transfer of cholesterol esters to other lipoprotein particles
apolipoprotein E
mediate remnant uptake
apolipoprotein A-1
activate LCAT
apolipoprotein C-II
cofactor for lipoprotein lipase
apolipoprotein B-48
mediate chylomicron secretion
apolipoprotein B-100
bind LDL receptor
LDL
transport cholesterol from liver to tissues
HDL
transport cholesterol from periphery to liver
chylomicron
dietary TGs to peripheral tissue
- deliver cholesterol to liver - after TGs removed
- as chylomicron remnant
secreted by intestinal epithelial cells - lymphatics
VLDL
deliver hepatic TGs to peripheral tissue
secreted by liver
IDL
degradation of VLDL
deliver TGs and cholesterol to liver
LDL
deliver hepatic cholesterol to peripheral tissues
formed by hepatic lipae of IDL in peripheral tissue
take up by target cells - receptor mediated endocytosis
HDL
cholesterol transport periphery to liver
repository for apolipoprotein C and E
-neede for chylomicron and VLDL metabolism
secreted from liver and intestine
alcohol
increased synthesis of HDL
type I dyslipidemia
hyperchylomicronemia
increased chylomicrons, TG, cholesterol
auto rec
deficient - lipoprotein lipase
or altered apolipoprotein C-II (cofacor for LPL)
pancreatitis, hepatosplenomegaly, eruptive xanthoma
no increased risk for atherosclerosis
type IIa dyslipidemia
familial hypercholesterolemia
increased LDL and choletserol
auto dominant
-absent or defective LDL receptors
heterozygote cholesterol of 300
homozygote cholesterol of 700+
accelerated atherosclerosis - MI age 20
tendon xanthoma, corneal arcus
type IV hypertriglyceridemia
elevated VLDL, TG
auto dom
hepatic overproduction of VLDL
hypertriglycemia - >1000
-may cause acute pancreatitis