fat metabolism 3 WF

Question 1

cholesterol structure and functions?

Answer 1

27 carbons, hydrophobic

component of membranes (particularly plasma membranes)
precursor of bile acids/salts
precursor of steroid hormones

Question 2

where is cholesterol mainly synthesised?

Answer 2

liver

Question 3

cholesterol synthesis?

Answer 3

starts with acetyl-CoA
3 join together
reduction by HMG-CoA reductase (regulatory step)
more intermediate steps to form cholesterol

Question 4

what is the principle regulator of HMG-CoA reductase? drugs that inhibit?

Answer 4

AMP-activated protein kinase
statins

Question 5

synthesis of bile acids?

Answer 5

cholesterol ->
hydroxylation and side chain cleavage
conjugation with taurine or glycine (amino acids) -> bile salts stored in gallbladder

(-> intestine)
hydrolysis and partial reduction
reabsorption of free bile acids and portal return to liver

Question 6

drugs acting on cholesterol balance?

Answer 6

statins (inhibit HMB-CoA reductase)
cholestyramine (absorbs bile acids, increases excretion - not used much)
plant sterols (inhibit uptake of cholesterol in intestine)
fibrates (lower triacylglycerol plasma levels, increase rate of LDL uptake into liver)