6 Endocrinology: Adrenal Hormones Flashcards
The 5 general functions of cortisol are? (global card)
- Mobilize/make glucose (plus stop using & store glucose)
- Mobilize amino acids and send them all to the liver
- Mobilize Fatty Acid (FA) stores
- Suppress immunity/inflammation
- Mature the CNS, retina, skin, lungs
What a simple way to remember catecholamine (from adrenal medulla) effects? (global card)
They are like thyroid hormone, but:
- No CNS effects
- Spares protein
- Short-acting
The 3 zones of cortex G-F-R release what hormones?
aldosterone, glucocorticoids, androgens
[deeper you go, sweeter it gets]
Which: cortex, or medulla? Is a modified sympathetic ganglion (lacking a post-ganglionic axon)
Medulla
Adrenal Medulla releases what?
catecholamines (norepi, epi) in response to sympathetic stimulation
Blood flow which direction in the adrenal glands? why does this matter?
- cortex->medulla
- One-two punch of hormones, and cortisol causes norepinephrin to become epinephrine.
So, what ARE the effects of catecholamines? (global card) (think of sympathetics)
- Up cardiac output, ventilation
- Mobilize fats
- Mobilize/make glucose but…
- Send all glucose to the brain
- Dilate pupils
- Decrease digestion
- Up muscle tension, neuromuscular transmission
The 4 catecholamine receptors are alpha 1 & 2, beta 1 & 2. Which catecholamine does not act on all 4?
Norepi (Doesn’t do beta 2’s)
What are catecholamines made from?
tyrosine
What is the steps by which catecholamines are made?
tyrosine-> L-Dopa-> Dopamine-> Norepi-> Epi
Which step of catecholamine synthesis is not regulated by ACTH, but by cortisol?
Norepi->Epi
Pheocromocytoma is a tumor where? Are symptoms continuous or sporadic?
- Adrenal medulla (chromaffin tissue)
- Sporadic
Pg. 6 has a figure showing cholesterol synthesis into steroids, tons of steps so easier to see in a graphic.
Now I’ll ask you 2 questions about it…
What receptor brings cholesterol into cells?
LDL receptor (also Acetyl CoA can be made into cholesterol)
What enzyme converts cholesterol into pregnenalone once StAR protein brings it into the mitochondria?
desmolase
As steroids, How are cortisol and aldosterone circulated?
Either bound or free
[cortisol w/ transcortin or albumin, aldosterone w/ plasma proteins]
What organ inactivates steroids?
liver!!!!!!!!!!!!!
What does aldosterone do? What would happen if you had too much/too little?
- Na reabsorb, K secrete
- Exactly what you would expect, EXCEPT in hyper-aldosterone, “escape” increases GFR and allows fluids and Na to leave body
As a steroid, where is aldosterone’s receptor located?
cytoplasm
As a steroid, what happens once aldosterone binds receptor?
disassociate hsp90, heads into nucleus, becomes a transcription factor
11 beta hydroxysteroid dehydrogenase Type 2 does what?
Degrades cortisol so it doesn’t bind aldosterone’s receptor and mimic aldosterone’s effect (licorice & stevia inhibit this enzyme, causing up blood pressure….)
What organs do the following: Secretes angiotensinogen? Secretes renin? Converts angiotensin 1? produces aldosterone?
- liver
- kidney
- lungs
- adrenal cortex
In order of importance, what causes aldosterone secretion?
-Up K+
-Renin system
-Down Na+
-ACTH
[ANP prevents secretion]
How does cortisol cause anti-inflammation? (global card)
- stabilize lysosomes
- decrease capillary permeability
- decrease WBC migration and phagocytosis
- decrease cellular glucose usage
- drops immune cell proliferation/Ab production
- inhibit NF-KappaB
What does cortisol do to vascular system?
maintains normal B.P.
What does cortisol do to kidneys?
Up GFR, more dilute urine
What does cortisol do to CNS?
modulate mood and sleep
What does cortisol do to lungs?
make surfactant
What does cortisol do to skin?
thins it
What turns on cortisol and ACTH?
stress, and mornings
Of the 3 short, ultra-short, and long-loop feedback, cortisol has which?
short, long
ACTH (stimulates cortisol release) comes from what pro-peptide? Why does this matter?
- POMC
- Because ACTH contains MSH in its sequence, increasing skin pigmentation
What is the rate-limiting step in steroid synthesis? What does ACTH do to this step?
- desmolase
- Activates it via cAMP
Combined cortisol/aldosterone deficiency is called what? What are the effects?
- Addison’s
- stress, skin darkening, hyperkalemia (heart block, vomiting, muscle weakness), decreased extracellular fluid volume, hypoglycemia
T/F Addison’s disease comes on quickly?
F
In hypersecretion of aldosterone, what happens to plasma renin concentration?
decreases (Diagnostic indicator! due to feedback inhibition)
Cushing’s disease is what?
adenoma causing cortisol secretion (responds to dexamethasone)
Cushing’s syndrome is what?
Other causes for cortisol over-secretion (WON’T respond to dexamethasone feedback inhibition)
[dexamethasone mimics cortisol]
What are the effects on the body of Cushing’s? (global card)
- up blood glucose
- Down immunity
- Thin skin
- Muscle weakness, bone weakness
- Hypertension (recall aldosterone, cortisol use same receptor…)
- Fat goes to chest/abdomen (buffalo hump!)
How would I treat Cushing’s?
remove or irradiate the pituitary or adrenal gland. (or use drugs that inhibit steroids)
In congenital adrenal hyperplasia, what is the mechanism?
-Broken enzyme stops cortisol & aldosterone synthesis->removes feedback inhibition->Tons of ACTH makes the adrenal gland huge.
[U.S. screens babies for this, it is autosomal recessive]
What body problems result from congenital adrenal hyperplasia?
salt-wasting, tons of androgens are made due to ACTH over-secretion
What is adrenogenital syndrome?
hairy woman, or penis growth to full-size occurs as a 4-year-old (due to DHEA)
