ADRENAL DISORDERS

Question 1

Which 3 kinds of steroid hormones does the adrenal cortex produce, with examples?

Answer 1

1. Sex steroids (e.g. androgens)
2. Mineralocorticoids (e.g. aldosterone)
3. Glucocorticoids (e.g. cortisol)

Question 2

Name 2 functions of mineralocorticoids

Answer 2

1. Mineral homeostasis (Increase Na+ and decrease K+)
2. Maintain blood volume

Question 3

What is the main function of glucocorticoids such as cortisol?

Answer 3

Helps body during exposure to stress

Question 4

Name 3 catabolic effects of glucocorticoids such as cortisol

Answer 4

1. Inhibits protein synthesis
2. Lipolysis
3. Promotes bone resorption

Question 5

Name 3 anabolic effects of glucocorticoids (e.g. cortisol)

Answer 5

1. Stimulates gluconeogenesis (conversion of proteins and fats into glucose)
2. Promotes liver glycogen synthesis and storage
3. Increases central fat deposition

Question 6

Why are glucocorticoids used therapeutically as anti-inflammatory and immunosuppressive drugs?

Answer 6

1. Decreases vascular permeability
2. Decreases WBCs and WBC activity
3. Inhibits cell mediated immunity

Question 7

What are 3 adverse effects of glucocorticoids?

Answer 7

1. Increases risk of infection
2. Decreased wound healing
3. Sodium + water retention

Question 8

What type of hormones does the adrenal medulla secrete?

Answer 8

Catecholamines (e.g. epinephrine and norepinephrine)

Question 9

Name 5 steps of adrenal gland regulation

Answer 9

1. Stimulus (e.g. stress)
2. Hypothalamus secretes CRH (corticotropin releasing hormone)
3. CRH stimulates anterior pituitary to release ACTH (adrenocorticotropic hormone)
4. ACTH stimulates adrenal cortex to secrete cortisol
5. Cortisol inhibits hypothalamus and anterior pituitary

Question 10

What are 2 terms for a condition of excess cortisol?

Answer 10

Hypercortisolism or Cushing syndrome

Question 11

What is the most common cause of Cushing syndrome?

Answer 11

Adverse effect of therapeutic glucocorticoids

Question 12

What is the cause behind primary hypercortisolism?

Answer 12

Adrenal hyperplasia or adrenal tumours that hypersecrete ACTH

Question 13

What is the cause behind secondary hypercortisolism, also called Cushing disease?

Answer 13

Pituitary adenoma that hypersecretes ACTH

Question 14

Besides adrenal hyperplasia, adrenal tumours, and a pituitary adenoma, what is another possible cause for excess ACTH leading to hypercortisolism?

Answer 14

Ectopic production of ACTH, e.g. small cell lung cancer

Question 15

Why do symptoms of hypercortisolism include muscle weakness and osteoporosis?

Answer 15

Cortisol inhibits protein synthesis causing muscle atrophy

Cortisol promotes bone resorption

Question 16

What are 2 metabolic effects of hypercortisolism?

Answer 16

1. Central fat deposition with thin limbs, leading to “moon face” or “buffalo hump”
2. Hyperglycemia & insulin resistance

Question 17

Why do symptoms of hypercortisolism including hypertension and hypokalemia?

Answer 17

Cortisol has a mineralocorticoid effect:

Promotes sodium and water retention

Promotes excretion of potassium in urine

Question 18

What symptoms may some women experience with hypercortisolism?

Answer 18

Androgen excess, leading to development of male secondary sex characteristics

Question 19

Why are purple striae (stretch marks) a symptom of hypercortisolism?

Answer 19

Decreased collagen (protein) formation

Question 20

What kind of lab test would help distinguish between a primary or secondary cause for hypercortisolism?

Answer 20

Plasma ACTH

(in primary hypercortisolism the ACTH level will be normal, while in secondary it will be high)

Question 21

What kind of test may be done to distinguish between Cushing disease and ectopic ACTH production, and why?

Answer 21

Dexamethasone suppression test

Dexamethasone is a cortisol analog:

If cortisol suppressed, means ACTH is being secreted by pituitary adenoma (affected by negative feedback)

If cortisol not suppressed, means ACTH is being produced ectopically (not affected by negative feedback)

Question 22

Name the 6 steps of the RAA pathway that results in aldosterone secretion by the adrenal cortex

Answer 22

1. Drop in blood pressure/volume
2. Kidneys release renin
3. Renin converts angiotensinogen (made by liver) into angiotensin I
4. Lungs release ACE independently
5. ACE converts angiotensin I into angiotensin II
6. Angiotensin II stimulates the adrenal cortex to release aldosterone

Question 23

What are the target tissues of aldosterone?

Answer 23

Distal tubules and collecting ducts in nephrons of kidneys

Question 24

What are 2 purposes of the sex steroids produced by the adrenal cortex?

Answer 24

1. Growth in children
2. Maintenance of pubic/axillary hair and libido in females

Question 25

What is the name of the cells of the adrenal medulla that produce catecholamines in response to sympathetic stimuli?

Answer 25

Chromaffin cells (pheochromocytes)

Question 26

What is the term for a chromaffin cell tumour?

Answer 26

Pheochromocytoma

Question 27

Which 3 symptoms form the "classic triad" associated with pheochromocytoma?

Answer 27

1. Headache 2. Tachycardia 3. Sweating