Steroids of the adrenal cortex

Question 1

What are the steroids of the adrenal cortex?

Answer 1

→ Glucocorticoids - cortisol
→ Mineralocorticoids - aldosterone
→ androgens

Question 2

What does aldosterone do?

Answer 2

→ Maintains blood volume by regulating Na+

Question 3

Where does the blood flow in the adrenal medulla?

Answer 3

→ Outer cortex to inner medulla

Question 4

What does steroid hormone synthesis always start with?

Answer 4

→ Cholesterol

Question 5

What does the cortex secrete?

Answer 5

→ Steroid hormones

Question 6

What does the medulla secrete?

Answer 6

→ Adrenaline

Question 7

What is the pathway in the zona glomerulosa?

Answer 7

Cholesterol
↓
Pregnenolone
↓ 
Progesterone
↓
Deoxycorticosterone
↓
Corticosterone
↓
Aldosterone

Question 8

What is the zona fasciculata pathway?

Answer 8

Progesterone
↓
17 OH progesterone
↓
Deoxycortisol
↓
Cortisol

Question 9

What is the zona reticularis pathway?

Answer 9

Pregnenolone 
↓
17 OH pregnenolone
↓
DHEA
↓ 
Androstenedione

Question 10

What is the function of mineralocorticoid?

Answer 10

→ Na+ retention
→ Active Na+ reabsorption
→ Active secretion of K+

Question 11

What is the juxtaglomerular apparatus stimulated by?

Answer 11

→ Increased sympathetic activity
→ Decreased perfusion pressure
→ Decreased Na+ and Cl-

Question 12

What stimulates aldosterone secretion?

Answer 12

→ K+

Question 13

How does aldosterone work to retain Na+?

Answer 13

→ Increases Na+/K+/ATPase activity on the apical side

Question 14

Why does cortisol not work in the kidney?

Answer 14

→ Cortisol levels are higher
→ Cortisol can stimulate the mineralocorticoid receptor
→ cortisol in the kidney gets converted to cortisone
→ by 11 beta HSD 2

Question 15

What is the syndrome of apparent mineralocorticoid excess?

Answer 15

→ Too much cortisol in the kidney

→ High BP

Question 16

What family is the glucocorticoid receptor a part of?

Answer 16

→ Nuclear receptor super family

Question 17

What are the 3 structural elements of the glucocorticoid receptor?

Answer 17

→ Ligand binding
→ DNA binding
→ N- terminal transcription co-factor binding

Question 18

What do the glucocorticoid receptors do when the ligand binds?

Answer 18

→ Receptors dimerize

→ Translocate to nucleus

Question 19

What is transactivation?

Answer 19

→ Glucocorticoid enhances transcription of the target gene

Question 20

What is transrepression?

Answer 20

→ Glucocorticoid represses the transcription of the target gene

Question 21

What are the functions of glucocorticoids?

Answer 21

→ Decreased glucose uptake
→ Increased proteolysis
→ Stimulates lipolysis 
→ Gluconeogenesis 
→ Maintaining glucose

Question 22

What does hypocortisolism lead to?

Answer 22

→ hypotension

→ Inappropriate vasodilation

Question 23

What are prostaglandins and leukotrienes derived from?

Answer 23

→ Lipid derived compounds

Question 24

What is the first molecule to be synthesized in the inflammation pathway?

Answer 24

→ Arachidonic acid

Question 25

What effect does cortisol have on the inflammation pathway?

Answer 25

→ Cortisol increases the expression of ANNEXIN - 1 | → Annexin 1 downregulates arachidonic acid

Question 26

What is the pathway for the production of cortisol?

Answer 26

``` → Hypothalamus makes CRH → CRH stimulates anterior pituitary → Anterior pituitary makes ACTH → ACTH stimulates the adrenal cortex → Adrenal cortex makes cortisol ```

Question 27

What is primary adrenal insufficiency?

Answer 27

→ Addisons disease

Question 28

What is secondary adrenal insufficiency?

Answer 28

→ Hypopituitarism → RAAS defect → Enzyme defect in steroid synthesis

Question 29

What are the clinical features of Addisons?

Answer 29

``` → Low adrenal steroids → high ACTH → Plasma Na+ - low → Plasma K+ - normal - high → high renin ```

Question 30

When there is very low cortisol what two hormones are high?

Answer 30

→ ADH - plasma dilution so low Na+ | → ACTH

Question 31

What is the ACTH receptor a part of?

Answer 31

→ Melanocortin group of receptors

Question 32

Why does Addisons cause hyperpigmentation?

Answer 32

→ Excess circulating ACTH → Binds to melanocortin receptors → Pigmentation

Question 33

What is Cushings disease due to?

Answer 33

→ Secondary | → Increased ACTH due to pituitary adenoma

Question 34

What is ACTH independent hypercortisolism?

Answer 34

→ Adrenal adenoma | → Iatrogenic

Question 35

What are clinical features of hypercortisolism?

Answer 35

``` → Hypertension → Hyperglycaemia → truncal obesity → Fatigue, Muscle weakness → Virilization → Depression ```

Question 36

What do low doses of dexamethasone usually do?

Answer 36

→ Suppress ACTH secretion via negative feedback

Question 37

What suppresses ACTH secretion in Cushings and why?

Answer 37

→ a higher dose of dexamethesone → Pituitary cells have increased → more cortisol/dexamethesone is needed for a negative feedback

Question 38

What happens if a high dose of dexamethesone does not suppress ACTH?

Answer 38

→ Ectopic source of ACTH