Biosynthesis of Steroid Hormones

Question 1

NE and E synthesis

Answer 1

cytosol:
-L-tyrosine > L dopa > dopamine

dopamine > VMAT-1 > chromaffin granule

granule:
dopamine > NE

NE > VMAT-1 > cytosol

cytosol:
NE (PMNT)> E
-stimulated by cortisol

Question 2

epinephrine

Answer 2

high affinity for beta-2 receptors

Question 3

exercise

Answer 3

skeletal m - beta 2 vasodilation
splanchnic arterioles - constriction
heart - beta 1 increased HR and contractility
veins - alpha vasoconstriction
beta-2 adipose, liver, muscle - more glucose
beta cells - alpha to decrease insulin
alpha cells - beta-2 to increase glucagon

Question 4

17 hydroxylase deficiency

Answer 4

CYP17 gene
lots of aldosterone
no androgen activity

HTN and hypokalemia

Question 5

21 hydroxylase deficiency

Answer 5

CYP21A2 gene
no aldosterone or cortisol
high androgens

hypotension, hyperlkalemia, virilization, hyponatremia

Question 6

11 hydroxylase deficiency

Answer 6

CYP11BR1 gene
low aldosterone and cortisol
excess androgens

HTN (due to DOC)
virilization

Question 7

ACTH

Answer 7

stimulates cholesterol uptake and conversion to pregnenolone

Question 8

steroid enzyme deficiencies

Answer 8

autosomal recessive mutations