Cholesterol Synthesis + Bile Flashcards
what are 3 functions of Cholesterol?
cell membranes, synthesize steroids (Vit D), Bile synthesis
Where does cholesterol synthesis start
cytoplasm
what increases cholesterol synthesis
lack of exercise + high sugar
how are steroid molecules named?
-one, -ol
name examples of steroid molecules/hormones
testosterone, estradiol, aldosterone, (pregnenolone, progesterone, cortisol, etc.)
name 2 disorders caused by excess Cholesterol
Cardiovascular disease, Gallstones
what test is used to diagnose problems in the gall bladder?
Cholecystogram (ultrasound of Gall Bladder)
what sources impact blood levels of Cholesterol
50% diet, 50% made by the body
3 locations of DeNovo synthesis of Cholesterol
*Liver, adrenal cortex, gonads
Number of Carbons in Cholesterol
27
List the order of steps for Cholesterol synthesis
Acetyl-CoA -(HMG CoA Synthase)-> HMG CoA -(HMG CoA Reductase + 2NADPH)-> Mevalonate -(ATP + Mg)-> Farnesyl Pyrophosphate -(Squalene synthase + NADPH + Mg + Mn)-> Squalene -(Cyclase + NADPH)-> Lanosterol -(NADPH)-> Cholesterol -(7-alpha-hydroxylase + NADPH + Vit C)-> Bile acids
stage 1 end product
Mevalonate
stage 1 enzymes
HMG CoA Synthase + HMG CoA Reductase
what foods have cholesterol?
animal products
stage 1 allosteric enzyme
HMG CoA Reductase
what co-enzyme does the allosteric enzyme in stage 1 require?
2NADPH
what hormone increases cholesterol synthesis
Insulin
name 2 things that down regulate cholesterol synthesis
Glucagon + Cholesterol
stage 2 end product
Farnesyl Pyrophosphate
stage 2 coenzymes required
ATP + Mg
the enzyme Farnesyl pyrophosphate is an important intermediate in the synthesis of ____
Co-Q10 (Ubiquinone, aka: Coenzyme Q10)
in the absence of the molecule CoQ10, what dose is needed to replete the drug induced nutrient deficiency?
100 mg/day
stage 3 end product
Squalene
what is Squalene capable of being?
a Ring
stage 3 enzyme
Squalene synthase
location of the enzyme squalene synthase
Endoplasmic reticulum
coenzymes for Squalene synthase
NADPH, Mg, Mn
stage 4 end product
Lanosterol
stage 4 enzyme
Cyclase
stage 4 coenzyme
NADPH (+H)
final product
Cholesterol
stage 5 (final stage) coenzyme required
NADPH
7 factors/lifestyle factors that impact cholesterol synthesis
high BP, smoking, male, decrease exercise, abdominal obesity, soft water, high serum free FA
largest product that cholesterol is used for
bile acids
enzyme required for production of bile acids
7-alpha-hydroxylase
coenzymes required for the enzyme 7-alpha-hydroxylase
NADPH, Vit C
what vitamin can be used in high doses to decrease blood cholesterol levels?
Niacin
what hormone increases the synthesis of bile?
Hepatocrinin
what causes the release of the hormone Hepatocrinin?
Fat in intestines (duodenum)
what hormone causes the gall bladder to contract?
Cholecystokinin
w/o fiber, how much bile is reabsorbed into the portal system and re-secreted?
98% (like reusing soap)
can cholesterol be digested or metabolized?
No
how much cholesterol is secreted in the feces?
1 gram
what do bacteria convert cholesterol to in the colon? what effect does this have?
Caprostanol; decrease amount of cholesterol you can absorb
define Steatorrhea
Foul smelling floating stool
Guinea pigs can get atherosclerosis if they are deficient in which Vitamin?
Vit C
natural dietary advice used to decrease blood LDL levels includes what two things?
Vit C + Bran
