Adrenal Gland

Question 1

What is secreted in the different parts of the adrenal gland?

Answer 1

cortex = corticoids and androgens

medulla = catecholamines

Question 2

In which CAH are sex hormones decreased?

Answer 2

defect in 17-alpha

Question 3

How does the cortisol affect the liver, muscle, fat, and skin?

Answer 3

liver = increased gluconeogenesis

muscle = breakdown of protein

fat = lipolysis in extremeties, central fat deposition

skin = breakdown of collagen –> thin skin, easy bruising

Question 4

How does cortisol affect the immune system, endocrine, and GI?

Answer 4

immune = depression

endocrine = insulin resistance, down regulates pituitary hormones

GI = interferes w/ Ca absorption –> risk of osteoporosis long-term

Question 5

How is cortisol regulated by hypothalamus and pit?

Answer 5

CRH released from paraventricular nucleus of hypothalamus –> CRF1 receptor in pituitary –> ACTH –> cortisol

cortisol does negative feedback to both hypothalamus and ant pit

Question 6

What is the ACTH molecule derived from and what is its significance to pigment?

Answer 6

derived from POMC –> ACTH in ant pit –> in non pituitary tissues, breaks down, contains MSH

MSH = melanocyte-stimulating hormone

excess ACTH –> hyperpigmentation

Question 7

How do CRH and ACTH affect each other?

Answer 7

CRH –> ACTH

ACTH has negative feedback to CRH

CRH also inhibits itself

Question 8

How do glucocorticoids specifically affect CRH and ACTH?

Answer 8

inhibit POMC transcription –> no ACTH

inhibit mRNA synthesis of CRH and ACTH

Question 9

What is the difference btw a low and high dose DST?

Answer 9

low dose = determines whether a problem is present; normal = suppression of ACTH and cortisol

high dose = determines the source of the problem

Question 10

What are the the results of high dose DST for pituitary cushing, adrenal cushing, and ectopic ACTH?

Answer 10

pituitary: supression of ACTH
adrenal: no suppression of cortisol
ectopic: no supression

Question 11

What is the Cosyntropin stim test?

Answer 11

Admin ACTH –> see what happens

healthy = cortisol should increase

adrenal insuffiency = no response

dramatic increase in cortisol –> could be secondary adrenal insufficieny

Question 12

What is the difference btw Cushing syndrome and Cushing Disease?

Answer 12

Cushing syndrome = umbrella term for high cortisol; non-pituitary cause

Cushing disease = pituitary tumor causing high cortisol

Question 13

What would the results be of a low dose ONDST for cushing syndrome and disease?

Answer 13

syndrome = ACTH suppressed, cortisol not suppressed

disease = ACTH not suppressed, cortisol suppressed

Question 14

What is Addison’s disease?

Answer 14

primary adrenal insufficiency

progressive destruction of adrenal gland

High ACTH but low cortisol

will fail cosyntropin stim test

Question 15

What is secondary adrenal insufficiency?

Answer 15

usually a pituitary problem

sometimes too much steriods –> decreases ACTH

see low ACTH and low cortisol

On cosyntropin stim test: cortisol will rise dramatically

Question 16

In what diseases would you see hyperpigmentation?

Answer 16

cushing disease (secondary cortisol excess)

Addison’s (primary adrenal insuficieny)

Question 17

How does Aldosterone affect the kidneys?

Answer 17

increases synthesis and activity of Na channels in apical membrane

Increases synthesis and activity of Na/K ATPase in the basolateral membrane of the distal tubule

overall = increased K excretion, increased sodium reabsorption

Question 18

What is Conn syndrome?

Answer 18

primary hyperaldosteronism = adrenal problem

usually neoplasm

see high BP and Na, low K

won’t change ACTH very much

low renin

Question 19

What is secondary hyperaldosteronism?

Answer 19

hypersecretion of renin by juxtaglomerular cells of kidney –> too much aldosterone

high BP and Na, low K

little change in ACTH

Question 20

What is hypoaldosteronism?

Answer 20

adrenal problem –> little aldosterone

low Na, high K

high renin (trying to raise aldosterone)

low BP

Question 21

What is secondary hypoaldosteronism?

Answer 21

Hyposecretion of renin –> not enough aldosterone

Low Na, high K

low BP

Question 22

How does ACTH affect cortisol and aldosterone?

Answer 22

affects cortisol much more

ACTH deficiency –> low cortisol, but little change in aldosterone

Question 23

What are the adrenal androgens and where are they from?

Answer 23

from zona reticularis –> DHEA and DHEAS –> precursors to sex hormones

rely on 3beta-HSD to exert activities

Question 24

How does the body stimulate catecholamine production?

Answer 24

Sympathetics –> ACh –> nicotinic receptors in adrenal medulla –> increased synthesis of tyrosine hydroxylase and activity of dopamine

Question 25

What is the rate limiting step of catecholamine synthesis?

Answer 25

tyrosine – tyr hydroxylase –> L-DOPA

Question 26

What is the general formation of catecholamines and where does it occur?

Answer 26

in cytoplasm: Tyr –> DOPA –> dopamine

in granule: Dopamine –> NE

cytoplasm: NE –> epi -> to granule again for release

Question 27

What does VMAT do?

Answer 27

moves Epi into specialized storage vesicles for release

Question 28

How are chromaffin granules released?

Answer 28

via exocytosis after sympathetic stimulation

Question 29

How are catecholamines broken down?

Answer 29

NE/E –> thru MAO –> thru COMT –> VMA

*VMA measurement can determine catecholamine production

Question 30

What is MAO?

Answer 30

oxidizes stuff

breaks down catecholamines

used to treat neuropsychiatric disorders

Question 31

What is COMT?

Answer 31

methylates stuff

primary enzyme that inactivates catecholamines released from the adrenal gland

Question 32

What do you see in pheochromocytoma?

Answer 32

usually benign and unilateral adrenal tumor

excess catecholamines

symptoms wax and wane (high bp, headaches, sweating)