Corticosteroids and the Stress Response

Question 1

What is a stressor?

Answer 1

A stimulus that disrupts homeostasis and cause the stress response.

Question 2

What are the two step physiological stress response?

Answer 2

1. Sympathetic nervous system (quick response within seconds which results in a release of adrenaline)/
2. HPA axis (slower response, results in release of cortisol)

Question 3

What are the immediate effects of the stress response?

Answer 3

• Increased HR,
• Increased oxygen intake,
• Increased blood glucose,
• Increased blood flow to muscles,
• Increased alertness,
• Inhibition of digestion and immune system,
• Release of endorphins,
• Dilation of pupils

Question 4

Chronic stress is related to what?

Answer 4

• Heart disease,
• Diabetes,
• Ulcers,
• Growth problems,
• Compromised immune system

Question 5

What is the relation between cortisol and depression?

Answer 5

Elevated cortisol seen in 50% of depressed patients.
Normal rhythm of cortisol production is high early in the morning.
Dexamethasone suppression test shows if their are abnormalities in cortisol levels

Question 6

Explain the relation of the stress response and the immune system

Answer 6

In first few mins, immune system is enhanced. After about an hour of stress the immune system returns to normal however chronic stress leads to immune system suppression.
Cortisol is immunosuppressive but also anti-inflammatory.

Question 7

Describe two examples of the modes of actions of glucocorticoids

Answer 7

Transactivation - Glucocorticoids cause activation of anti-inflammatory gene resulting in anti-inflammatory proteins being formed.
Transpression - Glucocorticoids cause inhibition of acting of inflammatory cytokines therefore inhibiting formation of inflammatory proteins.

Question 8

Name example of synthetic glucocorticoids of different potencies

Answer 8

Hydrocortisone (potency 1 of 8 hour half life),
Prednisolone (potency 4, half life of 16-36 hours),
Dexamethasone (potency 25-80, half life of 36-54 hours)

Question 9

What are the side effects of glucocorticoids?

Answer 9

• Systemic immunosupression,
• Hyperglycaemia,
• Skin fragility, and brusing,
• Osteoporosis,
• Weight gain,
• Adrenal insufficiency,
• Muscle brakdown,
• Irregular menstruation,
• CNS,
• Cushing’s syndrome

Question 10

What is the issue of withdrawal of glucocorticoids

Answer 10

Prolonged use of steroids causes adrenal atrophy so recovery can take months, so might want to taper down over days/months

Question 11

What are the two stages of type one diabetes development?

Answer 11

Stage 1 - Insulitis, lymphocyte invasion of pancreatic islets.
Stage 2 - Overt diabetes. Massive death of islet B cells resulting in loss of glucose homeostasis.