[4] Adrenal Glands

Question 1

Base Structure of Cortisol

Answer 1

Adrenocorticosteroid Nucleus

Question 2

What disease results from Hypercorticolism?

Answer 2

Cushing’s Syndrome

Question 3

What is the primary stimulus for Cortisol secretion?

Answer 3

ACTH

Question 4

What type of receptor is used in the synthesis of Cortisol?

Answer 4

GPCR

Question 5

Where is Cortisol synthesized?

Answer 5

Mitochondria (First Step)

Endoplasmic Reticulum

Question 6

Storage: Cortisol

Answer 6

Binds to Plasma Proteins

Question 7

Transport: Cortisol

Answer 7

Cortisol Binding Globulin: 75-80%
Albumin: 15%
Free Form: 6%

Question 8

Main Function of Cortisol

Answer 8

Conversion of Protein -> Glycogen

It is also weakly lipolytic, breaking down triglycerides to FFAs

Question 9

Relationship of Cortisol and Insulin

Answer 9

Antagonistic

Question 10

When are cortisol levels high?

When are they low?

Answer 10

H: Morning
L: Night

This changes depending on your sleeping pattern though, call center agents exhibit higher values at night

Question 11

Why are cortisol levels taken during night and day?

Answer 11

If it is consistently high, then it is indicative of hypercortisolism

Question 12

How does the Dexamethasone suppression test work?

Answer 12

Putting a synthetic steroid causes negative feedback on the hypothalamus and pituitary causing decreased levels of ADH and ACTH, thus lowering overall Cortisol levels

Question 13

Why is striae present in patients with Cushings?

Answer 13

Decreased collagen synthesis

Question 14

Function: Aldosterone

Answer 14

Reabsorption of sodium and tubular secretion of potassium in collecting tubules and distal tubules

Question 15

Where is Aldosterone synthesized?

Answer 15

Zona Glomerulosa ONLY because of aldosterone synthase

Question 16

2nd Messenger of Aldosterone Synthesis

Answer 16

IP3 + DAG

Question 17

2nd Messenger of Cortisol Synthesis

Answer 17

cAMP

Question 18

Transport: Aldosterone

Answer 18

Plasma Proteins: 50%

Free: 50%

Question 19

Which is more abundant, aldosterone or cortisol?

Answer 19

Cortisol is 100x more than Aldosterone

Question 20

Function: Enzyme HSD

Answer 20

Converts cortisol to corison, deactivating it, so that aldosterone is that one free to bind to the mineralocorticoid receptor

(Both cortisol and aldosterone can bind to the receptor but cortisol does not have the same effects)

Question 21

What enzyme converts cortisone -> cortisol?

Answer 21

11B-HSD1

It is present in skin so that when you place cortisone it can be activated

Question 22

Why is plasma renin activity suppressed when there is abundance of aldosterone?

Answer 22

Hypertension inhibits the renin system, indirectly caused by aldosterone

Question 23

Function: Adrenal Androgens

Answer 23

M: Nothing (Testosterone is much stronger)
F: Pubic and axillary hair growth

Question 24

Function: Phenylethanolamine-N-Methyltransferase

Answer 24

Norepinephrine -> Epinephrine

Question 25

Source: Epinephrine

Answer 25

ONLY Adrenal Medulla

High Epinephrine is indicative of a tumor in the adrenal medulla, high norepinephrine is not as specific

Question 26

Norepinephrine binds to which receptors more readily?

What about epinephrine?

Answer 26

N: Alpha receptors

E: Beta receptors

Question 27

Would there be weight loss if you have a tumor in your adrenal medulla?

Answer 27

Yes, catecholamines are extremely lipolytic