Therapeutic use of adrenal steroids Flashcards
What does the zona glomerulosa produce?
Aldosterone
What does the zona fasciculata produce?
Cortisol
What does the zona reticular produce?
Androgens and oestrogens
Which hormones are under the control of ACTH?
Cortisol and androgens
What stimulates aldosterone release?
Renin-angiotensin system
Where is renin produced?
Juxtaglomerular cells
What does renin do?
Converts angiotensinogen to angiotensin I
What does ACE do?
Converse angiotensin I to angiotensin II
What does angiotensin II do?
Stimulates release of aldosterone from adrenal cortex
What triggers aldosterone release?
Hyperkalaemia
Hyponatraemia
Drop in renal blood flow
Beta-1 adrenoceptor stimulation
Which adrenal steroid is essential for life?
Cortisol
Why are the principle physiological actions of adrenal androgens unknown?
Gonads are a much bigger source of androgens
What are the difference between glucocorticoid and mineralocorticoid receptors?
Glucocorticoid:
Wide distribution
Selective for glucocorticoids
Low affinity for cortisol
Mineralocorticoid:
Discrete distribution
Don’t distinguish between aldosterone and cortisol
High affinity for cortisol
Why is MRs lack of selectivity a problem?
Cortisol can stimulate them
How are MRs protected from cortisol?
Cortisol is converted to cortisone by 11beta hydroxysteroid dehydrogenase