Cholesterol Synthesis

Question 1

Substrate for Cholesterol Synthesis

Answer 1

Acetyl CoA

Question 2

Sites of Cholesterol Synthesis

Answer 2

All tissues in humans
MOST IMPORTANT: liver, intestine, adrenal cortex, ovarian, testes, placenta

CYTOSOL
ENDOPLASMIC RETICULUM

Question 3

Rate Limiting Step Cholesterol Synthesis

Answer 3

HMG CoA –> Mevalonate

HMG COA REDUCTASE
requires 2 NADPH

active in DEPHOSPHORYLATED state

Question 4

First cyclical compound and first steroid formed

Answer 4

LANOSTEROL

Question 5

Competitive inhibitors of HMG COA REDUCTASE

Answer 5

STATINS

Question 6

Synthesis of CoQ (ETC)

For synthesis of dolichol PPi for N linked glycosylation of proteins

Answer 6

FARNESYL PYROPHOSPHATE (PPI)

Question 7

(-) Cholesterol Synthesis

Answer 7

Glucagon

Glucocorticoids

Question 8

Specialized Products of Cholesterol

Answer 8

Bile Acids
Vitamin D
Sex Hormones
Corticosteroids

Question 9

7 dehydrocholesterol reductase deficiency

low plasma cholesterol and elevated dehydrocholesterol

Answer 9

SMITH LEMLI OPITZ SYNDROME

dysmorphic facial features
microcephaly
mental retardation
congenital heart disease
other malformations

Question 10

MC form of CAH (> 90%)

mineralocorticoids and glucocorticoids are absent or deficient

Answer 10

21 ALPHA HYDROXYLASE DEFICIENCY

overproduction of androgens –> masculinization of external genitalia in females and early virilization in males

Question 11

Decrease in serum cortisol, aldosterone and corticosterone

Increased production of deoxycorticosterone causes fluid retention

Answer 11

11 BETA HYDROXYLASE DEFICIENCY

overproduction of androgens –> masculinization and virilization