Mineralocorticoids and Aldosterone Flashcards Preview

Endo/Repro Exam 1 > Mineralocorticoids and Aldosterone > Flashcards

Flashcards in Mineralocorticoids and Aldosterone Deck (37):
1

What are the three layers of the adrenal cortex?

Zona glomerulosa
Zona fasciculata
Zona reticularis

2

What does the zona glomerulosa do?

Produces mineralocorticoids (aldosterone)

3

What does the zona fasciculata do?

Produces glucocorticoids (cortisol) and androgens

4

What does the zona reticularis do?

Produces androgens
Specialized to secrete Dihydroepiandrosterone

5

What does the adrenal medulla do?

Epinephrine
Small amount of norepinephrine

6

Largest region of the cortex?

Zona fasciculata

7

Key enzyme in the zona glomerulosa needed for mineralocorticoids?

21-hydroxylase enzyme

8

Key enzyme in the zona fasciculata needed for cortisol?

21-hydroxylase
11-Beta-hydroxylase

9

What is the common step to formation of all the steroids?

StAR needed for cholesterol to produce Pregnenolone

10

Most common abnormalities to form adrenal gland dysfunction?

21-hydroxylase
11-Beta-hydroxylase

11

What is the first step in steroid synthesis?

Get cholesterol into the mitochondria

12

What transports cholesterol into the mitochondria?

StAR protein

13

What generates Pregnenolone from cholesterol?

Cholesterol side-chain cleavage enzyme

14

GFR mnemonic:

G: Salt (mineralocorticoids)
F: Sugar (glucocorticoids)
R: Sex (androgens)

15

What does ACTH stimulate production of?

Both cortisol and adrenal androgens

16

What is the feedback for ACTH inhibition?

Cortisol only
No androgen feedback to inhibit ACTH

17

What receptor does ACTH stimulate?

MC2R (melanocortin-2 receptor)

18

What is the primary mediator of aldosterone release?

A-II; less so by ACTH and K+ levels

19

Three actions of aldosterone on the kidneys:

1.) Sodium and therefore passive water reabsorption
2.) Potassium absorption by the principal cells of the cortical CT
3.) Active secretion of protons via proton ATPases in lumenal membrane of IC of CT

20

Three major pathways regulating the secretion of renin by granular cells at the JGA:

1.) Renal baroreceptors: decreased perfusion = increased renin
2.) Macula densa: decreased Na/Cl ions in DCT = increased renin
3.) Sympathetic nervous system: increased activity increased renin release via beta receptors

21

How does A-II cause aldosterone release?

A-II binding to AT1 receptor causing IP3 binding to IP3R and release of intracellular Ca2+

22

What is the indirect method by which aldosterone inhibits ACTH release?

Systems effects of regulating blood volume and blood pressure leads to inhibition of ACTH release

23

What do principle cells express?

11beta-HSD2

24

What does 11beta-HSD2 cause?

Breaks down glucocorticoids so that they do not have as high of an affinity to the same receptors as mineralocorticoid receptors

25

What does glycyrrhetinic acid do?

Inhibits 11beta-HSD2

26

What is a common glycyrrhetinic acid?

Carbenoxolone

27

Half-life of aldosterone:

15-20 minutes

28

What is Conn's syndrome?

Primary hyperaldosteronism

29

What causes Conn's syndrome?

Autonomous benign tumors of the adrenal gland hyper-secrete aldosterone

30

What does Conn's syndrome cause?

Hypertension bc H20 and Na+ retention and hypokalemia bc excess K+ secretion and suppressed renin release

31

What is secondary hyperaldosteronism?

Renin overproduction

32

What can cause secondary hyperaldosteronism?

Decrease in effective arterial blood volume associated with ascites or heart failure leading to continuous stimulation of RAS system

33

What can cause primary hypoaldosteronism?

Plasma renin levels elevated due to primary adrenal insufficiency

34

What can cause secondary hypoaldosteronism?

Inadequate stimulation of aldosterone secretion despite normal adrenal function

35

How can mineralocorticoids cause kidney damage?

Production of ROS either by stimulation of NADPH oxidase or via mitochondria

36

What do ROS activated by mineralocorticoids cause in the kidney?

Podocyte damage, inflammation and fibrosis

37

How does aldosterone cause mesangial cell proliferation?

Activates P13K-AKT and MAPK causing transactivation of EGFR