Therapeutic Use Of Adrenal Steroids Flashcards

1
Q

Describe the production of adrenal steroids and their locations

A

Hypothalamus > CRH > anterior pituitary > ACTH > adrenal gland > cortisol.

  1. Zona fasiculata: cortisol
  2. Zona reticularis: androgens (oestrogen)
  3. Zona glomerulosa: aldosterone
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2
Q

Describe the process of release of aldosterone and its triggers

A

Aldosterone stimulated by the renin-angiotensin system. Renin from the juxtaglomerular cells in the kidneys converts angiotensinogen to angiotensin-1 and then ACE then angiotensin-II which stimulates the release of aldosterone from adrenal cortex

Triggers of aldosterone release: hyperkalaemia, hyponatraemia, drop in renal blood flow, beta 1 adrenoreceptor stimulation

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3
Q

What are the principle physiological actions of adrenal steroids

A

Cortisol, aldosterone (na retention, K loss)

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4
Q

Summarise the role of glucocorticoid and mineralcorticoid receptors.

A

Glucocorticoid:

  1. Wide distributions
  2. Selective for glucocorticoid
  3. Low affinity for cortisol

Mineralcorticoid

  1. Discrete distribution (kidneys)
  2. Do not distinguish between aldosterone and cortisol
  3. High affinity for cortisol
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5
Q

Discuss the drug-receptor selectivity of hydrocortisone, prednisolone, dexamethasone, fludocortisone

A
  1. Hydrocortisone (like cortisol GR, MR activity - overwhelms 11bhsd)
  2. Prednisolone (GR with little MR)
  3. Dexamethasone (synthetic glucocorticoid no MR)
  4. Fludocortisone (aldosterone analogues)
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6
Q

Describe the corticosteroid replacement therapy

A
  1. Primary adrenocortico failure: addisons: patients lack cortisol and aldosterone (treat with hydrocortisone and fludrocortisone)
  2. Secondary adrenocortical failure: ACTH deficiency (low cortisol), treat with hydrocortisone
  3. Acute adrenocortical failure: addisonian crisis
  4. congenital adrenal hyperplasia (CAH)
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7
Q

Explain CAH

A

Lecture

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