BSI 2 Lecture 50: Adrenal Gland

Question 1

What two portions make of the adrenal gland?

Answer 1

The adrenal cortex and adrenal medulla

Question 2

What does the adrenal medulla secrete?

Answer 2

The catecholamines: epinephrine and norepinephrine

Question 3

What does the adrenal cortex secrete?

Answer 3

Corticosteroids (aldosterone, cortisol, cortisone, and androgens)

Question 4

What are the three layers of the adrenal cortex?

Answer 4

Zona glomerulosa, zona fasciculata, and zona reticularis

Question 5

What does the zona glomerulosa secrete?

Answer 5

aldosterone because it expresses aldosterone synthase

Question 6

What does the middle zona fasciculata secrete?

Answer 6

cortisol and related corticosterone plus androgen and even some estrogen

Question 7

What does the zona reticularis secrete?

Answer 7

Androgens, androstenedione, and small amounts of estrogen and glucocorticoids

Question 8

What are the steroid hormones derived from?

Answer 8

Cholesterol

Question 9

How are steroid hormones formed?

Answer 9

1) ACTH binds to GPR
2) Activates AC to produce cAMP
3) cAMP activates PKA
4) PKA phosphorylates cholesterol esterase
5) Cholesterol esterase separates cholesterol from LDL
6) Cholesterol is transported to the mitochondria by StAR
7) Then it’s transported to the inner membrane by PBR
8) p450 enzymes modify cholesterol
9) Enzyme profile determines which steroid is produced

Question 10

Aldosterone has a greater effect on sodium retention whereas cortisol is equally effective at _______.

Answer 10

sodium retention and suppressing inflammation

Question 11

What percentage of plasma cortisol is bound to cortisol-binding globulin (Transcortin)?

Answer 11

90-95%

Question 12

Why does aldosterone have a shorter half life?

Answer 12

Because only about 60% is bound to proteins

Question 13

How are corticosteroids metabolized?

Answer 13

They are metabolized in the liver by conjugation to glucuronic acid which makes them more water soluble and about 75% is excreted by the kidneys while the other 25% is excreted in the feces via bile

Question 14

What controls the release of Cortisol from the adrenal cortex?

Answer 14

Corticotropin releasing hormone from the hypothalamus, antidiuretic hormone from the posterior pituitary, and Andrenocorticotropic hormone from the anterior pituitary

Question 15

What could potentially be a negative regulator of corticotropin releasing hormone?

Answer 15

Somatostatin

Question 16

When are CRF, ACTH, and cortisol levels high?

Answer 16

Early in the day (6-8am)

Question 17

What happens when there is a glucocorticoid imbalance?

Answer 17

there are serious effects on metabolism and the body’s ability to handle stress

Question 18

Which glucocorticoid is secreted the most?

Answer 18

Cortisol (95%)

Question 19

What are the glucocorticoids going to do in the liver?

Answer 19

Stimulate gluconeogenesis by increasing level of enzymes to convert AAs into glucose and increasing the release of AAs from muscle for gluconeogenesis

Question 20

What effect can cortisol have on insulin?

Answer 20

It can cause decrease utilization of glucose in the cells; therefore, there is an increase in blood glucose which stimulates insulin release. However, insulin’s effectiveness in decreasing blood glucose is reduced

Question 21

What could happen to blood sugar in regards to cortisol release?

Answer 21

It could increase to 50% greater than normal which is called adrenal diabetes, and insulin is not very effective in combatting this scenario

Question 22

List the functions of glucocorticoids

Answer 22

1) Increased protein synthesis in liver
2) Increased lipolysis
3) Gluconeogenesis
4) Increase insulin resistance
5) Decrease inflammation
6) Decrease immune function

Question 23

List functions of the catecholamines

Answer 23

1) Increased blood pressure
2) Increased heart rate
3) Increased blood sugar
4) Decreased GI blood flow

Question 24

What does cortisol do to proteins outside of the liver?

Answer 24

Decreases them by decreasing synthesis and increasing catabolism

Question 25

What does cortisol do to fat metabolism?

Answer 25

It will increase the oxidation of fatty acids from adipose tissue but over a longer period of time than what happens with decreased blood sugar

Question 26

What factor can trigger the release of cortisol?

Answer 26

Almost any type of stress

Question 27

What is the significance of cortisol release during stress?

Answer 27

It saves proteins from being broken down until there is no other option

Question 28

What can high doses of cortisol do to inflammation?

Answer 28

Decrease inflammation by…

1) Decreasing the number of proteolytic enzymes
2) Decreasing capillary permeability
3) Decreasing prostaglandin production
4) Suppressing T-lymphocytes
5) Decreasing the release of interleukin-1
6) Decreasing the number of eosinophils and lymphocytes

Question 29

What androgen is produced in the highest number by the adrenal cortex?

Answer 29

DHEA