biosynthesis of steroid hormones Flashcards
What does the adrenal medulla produce
catecholamines, norepi and mainly epi
what is synthesis of catecholamines regulated by
CRH-ACTH axis
ACTH stimulates what
synthesis of DOPA
High levels of cortisol have what affect on catecholamines
PMNT enzyme increases, which converts norepi to epi
Where is the synthesis of norepi
granules
where is the synthesis of epi
in the cytosol
What are the 2 enzymes in catecholamine degradation
MAO
COMT catecholamine O methyltransferase
When assaying for catecholamines what are you usually measuring
the degradation products in the urine
How are adrenergic R classified
potency
downstream signaling pathways
location and density
What is the role of activated alpha 1 R
vasc sm mm contraction
What is the role of activated alpha 2 R
inhibits norepi and insulin release
What is the role of activated B1 R
increase CO
What is the role of activated B3 R
increase glucose output and vasodilates
constant stimulation of alpha R have what effect on vasculature
chronic venoconstriction
what is the main role of cortisol
increase plasma glucose
responds to stress
influences glucose utilization, immune and inflammatory homeostasis
What hormones are produced in adrenal cortex
mineralocorticoids
glucocorticoids
Androgens (DHEA)
what is the backbone for all steroid hormones
cholesterol
what is the first steroid produced from cholesterol
pregnalone
What steroids can we get from pregnalone
progesterone via 3 beta hydroxylase
17 alpha hydroxylase can make it 17alpha pregnalone
What converts progesterone to deoxy corticosterone
21 hydroxylase
what is the purpose of 11 beta hydroxylase
take deoxycorticosterone to corticosterone
what can corticosterone become
aldosterone (aldosterone synthase)
regulated by RAAS
cortisol by 17 alpha hydroxylase
describe deficiency in 17 alpha hydroxylase
Everything is shunted to mineralocorticoid
cannot produce glucocorticoids or androgens
describe deficiecy in 21 hydroxylase
cannot produce mineralocoritcoids and glucocorticoids
shunted into androgens
describe deficiency in 11 beta hydroxylase
cannot produce glucocorticoids
some mineralocorticoids
shunted mainly to androgens
What is congenital adrenal hyperplasia
group of autosomal recessive disorders
deficiency in either cotrisol, aldosterone or both
When adrogen levels are high what happens
virilization
what enzyme deficiencies can lead to high adrenal androgens
21-hydroxylase
11beta hydroxylase
What enzyme deficiency leads to a high mineralocorticoid effect
17 alpha hydroxylase
hypertensive
what enzyme deficiency leads to excess deoxycotricosterone
11 beta hydroxylase
What are the signs of 21 hydroxylase deficiency
salt wasting hyponatremia hyperkalemia hypotension CV collapse virilization
describe the two types of deficiencies of 21 hydroxylase
total or partial
What does the 11 beta hydroxylase do
converts desoxycortisol to cortisol
What happens in 11 beta hydroxylase deficiency
loss neg feedback inhibition and ACTH mediated adrenal androgen excess is the result
What causes the hypertension in deficient 11 beta hydroxylase
increased secretion of deoxycorticosterone
Is there any cortisol in a person with 11 beta hydroxylase deficiency
no
how do you differentiate between 11 beta and 21 hydroxylase deficiencies
no salt wasting that you see in 21 hydroxylase
what type of mutation is are the steroid hormone deficiencies
autosomal recessive
What leads to hypertension and hypokalemia in 17alpha hydroxylase deficiency
excess intermediary steroids with mineralocorticoid activity
what would be the aldosterone, K, Na, renin levels would be in someone with 21 hydroxylase deficiency
low aldosterone
low Na
high K
renin is increased
17 y/o female, no menses, no pubic hair, no breast development, hypertensive
frequent headaches
hypokalemia, hypernatremia and metabolic alkalosis, low 17-ketosteroids, serum estrogen, increased progesterone, prenelone and 11 deoxycoricosterone and coricosterone
deficient 17 alpha hydroxylase, partial because later in life
