Therapeutic Use Of Adrenal Steroids Flashcards
Describe the production of adrenal steroids and their locations
Hypothalamus > CRH > anterior pituitary > ACTH > adrenal gland > cortisol.
- Zona fasiculata: cortisol
- Zona reticularis: androgens (oestrogen)
- Zona glomerulosa: aldosterone
Describe the process of release of aldosterone and its triggers
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
What are the principle physiological actions of adrenal steroids
Cortisol, aldosterone (na retention, K loss)
Summarise the role of glucocorticoid and mineralcorticoid receptors.
Glucocorticoid:
- Wide distributions
- Selective for glucocorticoid
- Low affinity for cortisol
Mineralcorticoid
- Discrete distribution (kidneys)
- Do not distinguish between aldosterone and cortisol
- High affinity for cortisol
Discuss the drug-receptor selectivity of hydrocortisone, prednisolone, dexamethasone, fludocortisone
- Hydrocortisone (like cortisol GR, MR activity - overwhelms 11bhsd)
- Prednisolone (GR with little MR)
- Dexamethasone (synthetic glucocorticoid no MR)
- Fludocortisone (aldosterone analogues)
Describe the corticosteroid replacement therapy
- Primary adrenocortico failure: addisons: patients lack cortisol and aldosterone (treat with hydrocortisone and fludrocortisone)
- Secondary adrenocortical failure: ACTH deficiency (low cortisol), treat with hydrocortisone
- Acute adrenocortical failure: addisonian crisis
- congenital adrenal hyperplasia (CAH)
Explain CAH
Lecture