L73: HPA Axis & Adrenal (part II)

Question 1

What is the biologically active precursor of Aldosterone

Answer 1

11-DOC

Question 2

What enzyme deactivates cortisol into cortisone?

Answer 2

11B-HSD2

Question 3

What enzyme deactivates cortisol into cortisone, in mineralocorticoid target cells?

Answer 3

11B-HSD2.

The big idea here is that cortisol isn’t supposed to act on mineralocorticoid target cells, but glucocorticoid target cells.

Question 4

What enzyme reactivates cortisone to cortisol, in glucocorticoid target cells?

Answer 4

11B-HSD1

Question 5

What drug inhibits 11B-HSD2, resulting in excess MR activation?

Answer 5

Carbenoxolone

Question 6

What does licorice do?

Answer 6

Inhibits 11B-HSD2, thereby preventing the inactivation of cortisol to cortisone in MR target cells.

Question 7

What does licorice (glycrrhetinic acid) do?

Answer 7

Inhibits 11B-HSD2, thereby preventing the inactivation of cortisol to cortisone in MR target cells.

Question 8

What are the 3 layers of the adrenal cortex?

Answer 8

Zona glomerulosa
Zona fasciculata
Zona reticularis

“GFR”

Question 9

What layer of the adrenal cortex makes mineralocorticoids (eg. Aldosterone)?

Answer 9

Zona glomerulosa

Question 10

What layer of the adrenal cortex makes glucocorticoids (eg. cortisol)?

Answer 10

Zona fasciculata

Question 11

What innervates the adrenal medulla?

Answer 11

Splanchnic nerve

Question 12

High ACTH and no cortisol. This drives the synthesis of

Answer 12

norepinephrine

Question 13

Only in the adrenal medulla, cortisol stimulates the conversion of

Answer 13

norepinephrine to epinephrine.

Question 14

High ACTH and no cortisol. This drives the synthesis of

Answer 14

norepinephrine (normally Epi is the dominant one)

Question 15

21a hydroxylase deficiency

Answer 15

Congenital Adrenal Hyperplasia

Question 16

Hypotension
Hyperkalemia
High plasma renin
Masculinization
High ACTH

Answer 16

CAH

Question 17

Hypertension
Hypokalemia
Masculinization
High ACTH

Answer 17

2nd most common cause of CAH:

CYP11B1: 11-hydroxylase deficiency

Question 18

Hypertension
Hypokalemia
Masculinization
High ACTH

Answer 18

2nd most common cause of CAH:

CYP11B1, 11-hydroxylase deficiency

Question 19

What is the metabolic byproduct of catecholamine catabolism by COMT and MAO, that is excreted in urine?

Answer 19

VMA (vanillylmandelic acid)

Question 20

High urinary VMA may indicate

Answer 20

EPI/NE producing tumors

Question 21

Pheochromocytoma

Answer 21

tumor originating from chromatin cell

Question 22

Pheochromocytoma

Answer 22

tumor originating from chromatin cell.

Question 23

Why is pheochromocytoma called a “10% tumor”?

Answer 23

10% are malignant
10% are bilateral
10% in children
10% familial
10% recur
10% associated with MEN
10% present with a stroke
10% extra-adrenal

Question 24

ONLY IN THE ADRENAL MEDULLA, cortisol stimulates the conversion of

Answer 24

norepinephrine to epinephrine.

Question 25

What do patients with 21a-hydroxylase or 11beta-hydroxylase deficiencies have in common?

Answer 25

Excess ACTH (lack of negative feedback, since no cortisol)

Question 26

Steroidogenic regulatory protein

Answer 26

transfers cholesterol from the outer mitochondria to the inner mitochondria

Question 27

``` Which of the following is regulated by ACTH? A. StAR B. Cholesterol ester hydrolase C. ....add more D. All of the above ```

Answer 27

D.

Question 28

What zone of the adrenal gland does 11-hydroxylase (CYP11B1) live?

Answer 28

Z. fasciculata

Question 29

What zone of the adrenal gland does CYP11B2 11-hydroxylase live?

Answer 29

Z. glomerulosa

Question 30

Where in the adrenal gland is 17alpha-hydroxylase (CYP17)

Answer 30

Z. fasciculata and reticularis

Question 31

Is 11B-HSD1 and 2 in the p450 family? Where does it live?

Answer 31

No. Kidney (type 2)

Question 32

What's another name for aldosterone synthase?

Answer 32

CYP11B2

Question 33

Where does CYP11B2 live?

Answer 33

Zona glomerulosa

Question 34

Adrenal medulla is derived from

Answer 34

neural crest cells

Question 35

Preganglionic neuron to adrenal neuron comes from

Answer 35

splanchnic nerve

Question 36

Rate limiting step for dopamine synthesis?

Answer 36

Tyrosine hydroxylase

Question 37

High ACTH but low cortisol. Will you lack: A. Dopamine B. NE C. Epi

Answer 37

C. Epi

Question 38

George has high BP that is unresponsive to BP lowering meds. What should you check for?

Answer 38

Look at VMA in urine. Think: Pheochromocytoma is unresponsive to B-blocker