Lipid Metabolism

Question 1

What is the role of CETP?

Answer 1

collects TGs from VLDL or LDL and exchanges for CEs from HDL

Question 2

What does LCAT do?

Answer 2

it is bound to HDLs and LDLs & converts free cholesterol into cholesterol ester, sequestering into hydrophobic core of lipoprotein.

Question 3

How is HSL activated and by what?

Answer 3

Phosphorylation by ACTH, noradrenaline, glucagon, adrenaline.

Question 4

What is the link between fatty acids and caveolae?

Answer 4

CAV1 is a FABP and moves from PM to lipid droplets in response to FFAs.
Mice knockouts are resistant to diet induced obesity and show decreased adiposity.

Question 5

Outline foam cells.

Answer 5

LDL –> intima space and oxidised by macrophages.

No longer recognised by liver –> recognised by macrophages as foreign.

Phagocytosed & excess cholesterol stored.

Macrophage becomes dysfunctional.
Recruits other immune cells (adhere to endothelium)

Atherosclerotic plaques develop.

Question 6

What is a biological requirement for highly UFAs?

Answer 6

Membrane spanning proteins create curvature stress and therefore need these.

Question 7

Why does consuming high amounts of plant sterols lower circulating cholesterol?

Answer 7

More active expelling THEM from gut.
Net reabsorption of endogenous cholesterol from gut becomes more negative.
More cholesterol must be absorbed FROM CIRCULATION by liver.

Question 8

What is SD-LDL?

Answer 8

Atherogenic lipoprotein

If LDL not cleared from liver then further delipidated

Question 9

What is lp(a)?

Answer 9

B100 and apo(a)

Question 10

When are the following pathways in use?
Exogenous
Endogenous
Reverse

Answer 10

Early postprandial in fed state
Late postprandial in fed / fasted
Always in fed / fasted.