Glucocorticoids

Question 1

How does the H-P-A axis regulate synthesis and secretion of adrenal corticosteroids?

Answer 1

1. Hypothalamus releases cortictropin releasing factor (CRF)
2. CRF induces release of ACTH from anterior lobe of pituitary
3. ACTH acts on adrenal glands to release glucocorticoids
4. Glucocorticoids produce negative feedback on hypothalamus to reduce CRF secretion

Question 2

What are the three zones of the adrenal cortex and what do they produce?

Answer 2

1. Zona glomerulosa - GCs
2. Zone fasciltata - MCs
3. Zona reticularis - Sex hormones

Question 3

What two hormones positively regulate steroid synthesis and how?

Answer 3

ACTH and angiotensin II increase side chain cleavage (SCC) activity to increase conversion of cholesterol to pregnenolone

Question 4

Which drug blocks SCC?

Answer 4

Aminoglutehimidie - stops production of ALL steroids.

Question 5

Effects of glucocorticoids and mineralocorticoids

Answer 5

Glucocorticoids:

• CHO metabolism
• Protein catabolism
• Adipose tissue redistribution
• Ant-inflammatory/immunosuppressive effects

Mineralocorticoids:

• Water and electrolye homestasis:
  
  • Na+ and H2O retention
  • K+ and H+ excretion