Metabolism V

Question 1

rate limiting step cholesterol synthesis

Answer 1

HMG CoA reductase

inhibited by statins
-competitive and reversible

Question 2

insulin

Answer 2

induces HMG CoA reductase

Question 3

pancreatic lipase

Answer 3

degration of dietary TGs in small intestine

Question 4

lipoprotein lipase

Answer 4

degradation of TGs circulating in chylomicrons and VLDLs

found on vascular endothelial surface

Question 5

hepatic TG lipase

Answer 5

degradation of TGs remaining in IDL

Question 6

hormone sensitive lipase

Answer 6

degradation of TGs stored in adipocytes

Question 7

LCAT

Answer 7

esterification of cholesterol

Question 8

cholesterol ester transfer protein (CETP)

Answer 8

mediate transfer of cholesterol esters to other lipoprotein particles

Question 9

apolipoprotein E

Answer 9

mediate remnant uptake

Question 10

apolipoprotein A-1

Answer 10

activate LCAT

Question 11

apolipoprotein C-II

Answer 11

cofactor for lipoprotein lipase

Question 12

apolipoprotein B-48

Answer 12

mediate chylomicron secretion

Question 13

apolipoprotein B-100

Answer 13

bind LDL receptor

Question 14

LDL

Answer 14

transport cholesterol from liver to tissues

Question 15

HDL

Answer 15

transport cholesterol from periphery to liver

Question 16

chylomicron

Answer 16

dietary TGs to peripheral tissue

• deliver cholesterol to liver - after TGs removed
• as chylomicron remnant

secreted by intestinal epithelial cells - lymphatics

Question 17

VLDL

Answer 17

deliver hepatic TGs to peripheral tissue

secreted by liver

Question 18

IDL

Answer 18

degradation of VLDL

deliver TGs and cholesterol to liver

Question 19

LDL

Answer 19

deliver hepatic cholesterol to peripheral tissues

formed by hepatic lipae of IDL in peripheral tissue

take up by target cells - receptor mediated endocytosis

Question 20

HDL

Answer 20

cholesterol transport periphery to liver

repository for apolipoprotein C and E
-neede for chylomicron and VLDL metabolism

secreted from liver and intestine

Question 21

alcohol

Answer 21

increased synthesis of HDL

Question 22

type I dyslipidemia

Answer 22

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

Question 23

type IIa dyslipidemia

Answer 23

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

Question 24

type IV hypertriglyceridemia

Answer 24

elevated VLDL, TG

auto dom
hepatic overproduction of VLDL

hypertriglycemia - >1000
-may cause acute pancreatitis