Adrenal Steroids - Physiological Effects

Question 1

What is the primary action of the mineralocorticoids (Aldosterone)?

Answer 1

Maintain Na/K balance via mineralocorticoid receptors in the kidney. Sodium in, Potassium and Hydrogen out.

Question 2

Is cortisol an agonist or antagonist at which receptor?

Answer 2

Agonist at the MR (minerocorticoid) receptor with 10x more affinity for the MR receptor than the GR (glucocorticoid) receptor

Question 3

Which is the physiological mineralcorticosteroid?

Answer 3

Aldosterone, not cortisol because in the kidney cortisol is inactivated by 11betaHSD2 which converts it to cortisone

Question 4

Which are the glucocorticoids?

Answer 4

Corticosterone and cortisol

Question 5

What blocks 11betaHSD2?

Answer 5

Black licorice

Question 6

What happens to people with a mutation of 11betaHSD2?

Answer 6

They get hypertension

Question 7

What does 11betaHSD2-I do?

Answer 7

Reverse of 11betaHSD2, it takes cortisone and converts it to cortisol in the liver (vs 11betaHSD2 which converts cortisol to cortisone in the kidney)

Question 8

Which amino acids do glucocorticoids send to the liver for gluconeogenesis?

Answer 8

Alanine and Glutamine

Question 9

What are the actions of the glucocorticoids (corticosterone and cortisol) in the liver?

Answer 9

Gluconeogenesis (synthesis) and glycogenesis (storage) of glucose in the liver

Question 10

What are the actions of the glucocorticoids (corticosterone and cortisol) in the periphery?

Answer 10

1 - Decrease peripheral uptake of glucose from blood into tissues
2 - Enhance peripheral protein breakdown (increase blood amino acids)
3 - Cause central redistribution of fat (increases insulin release and lipogenesis) especially around the peritoneum

Question 11

What are the actions of the glucocorticoids (corticosterone and cortisol) on tissue responsiveness?

Answer 11

Enhance tissue responsiveness to EPI and NE (fat mobilization and responsiveness of vascular smooth muscle)

Question 12

What are the actions of the glucocorticoids (corticosterone and cortisol) on inflammation?

Answer 12

• Anti-inflammatory (inhibit capillary permeability)
• Inhibit endothelial “sticking” of leukocytes through capillary walls (squeeze through the walls)
• Prevent release of acid hydrolyses which perpetuate inflammation (acid soup)
• Inhibit formation of prostaglandins, thromboxanes, leukotrienes by inducing lipocortin which inhibits phospholipase A2
• Inhibit histamine release from basophils

Question 13

What are the actions of the glucocorticoids (corticosterone and cortisol) on the immune system?

Answer 13

• Immunosuppressive effects
• Decreases B and T cells.
• Decrease cytokine production

Question 14

What are the actions of the glucocorticoids (corticosterone and cortisol) on the skeleton?

Answer 14

• Large doses decrease calcium absorption from the GI and increase calcium excretion by antagonizing active Vitamin D
• Decrease bone formation due to inhibition of collagen formation (increased risk of osteoporosis)
• Inhibit osteoblast function, enhance osteoclast
• Decrease OPG release and increase RANKL

Question 15

What are the actions of the glucocorticoids (corticosterone and cortisol) on the GI?

Answer 15

Enhances gastric acid secretion to cause ulcers (more often seen with exogenous administration of supraphysiological doses of synthetic cortisol

Question 16

What is the number 1 use of glucocorticoids?

Answer 16

Anti inflammatory

Question 17

What are the actions of the glucocorticoids (corticosterone and cortisol) on the lungs?

Answer 17

Increase lung surfactant

Question 18

Are glucocorticoids anabolic or catabolic?

Answer 18

Catabolic. Inhibit the release of growth hormone (problem in kids with asthma - stunts their growth). You are breaking down muscle mass to generate amino acids for gluconeogenesis

Question 19

What are the actions of the glucocorticoids (corticosterone and cortisol) on blood pressure?

Answer 19

Increases blood pressure by several actions, one is antagonism of vasopressin (explains the hyponatremia seen in patients with glucocorticoid deficiency)

Question 20

Why are glucocorticoids used in certain cancer treatments?

Answer 20

Inhibit polyamine synthesis leading to decreased cell growth and proliferation. Used in MOPP therapy.

Question 21

What hormones does cortisol suppress at the pituitary?

Answer 21

ACTH
GH
TSH
LH
FSH
(negative feedback)

Question 22

How do glucocorticoids affect the heart?

Answer 22

Enhance pressor effects of catecholamines on vascular smooth muscle. Increase force of contraction of the heart and increase cardiac output.