8) Therapeutic use of adrenal steroids Flashcards
3 stimuli for renin release:
1) decreased Na+ reabsorption
2) decreased renal perfusion pressure
3) increased SNS activity
3 arms of adrenal cortex steroid synthesis:
1) Glucocorticoid-cortisol
2) Mineralocorticoid-aldosterone
3) Sex steroids
2 types of corticosteroid receptors and 3 facts about them:
Glucocorticoid receptor
- wide distrubution
- only binds to cortisol
- low affinity for cortisol
Mineralocorticoid receptor
- discrete distribution-only in kidney
- binds to both cortisol + aldosterone
- high affinity for cortisol
If cortisol can bind to both GR & MR receptors why do we even need aldosterone?
In the kidney there is 11B-hydroxysteroid dehydrogenase 2 which inactivates cortisol–>cortisone
What happens to 11B-hydrozysteroid dehydrogenase 2 in Cushing’s?
In cushing’s (excess ACTH) 11B-hydroxysteroid dehydrogenase 2 is overwhelmed so cortisol binds to MR=mineralocorticoid like effects
4 types of corticosteroid drugs that can be given?
Hydrocortisone-glucocorticoid with mineralocorticoid like activity at high dose
Prednisolone-glucocorticoid with weak mineralocorticoid like acivity
Dexamethosone-glucocorticoid with NO mineralocorticoid activity
Fludrocortisone-aldosterone analogue
What are the 2 differences between hydrocortisone and prednisolone?
1) hydrocortisone has mineralocorticoid like activity at high doses whereas prednisolone only has weak mineralocorticoid activity
2) hydrocortisone is quickly metabolised so given a few times a day whereas prednisolone is only given once a day
2 ways corticosteroids can be administered?
Oral Parentral (IV/IM)-if large dose is needed quickly
2 ways corticosteroids are distrubuted around the body?
PPB
- Cortisol binding globulin
- Albumin
How is Addison’s disease treated?
1) NaCl
2) Hydrocortisone
3) Fludrocortisone
What type of disease is Addison’s disease?
Primary-adrenal cortex (the endocrine gland itself) is destroyed
How is an addisonian crisis treated (acute adrenocortical crisis)?
1) 0.9% NaCl
2) high dose hydrocortisone
3) 0.5% dextrose if hypoglycaemic
What is secondary adrenocortical failure?
Pituitary gland isnt producing any ACTH
- no cortisol
- aldosterone is fine
How is secondary adrenocortical failure treated?
Just hydrocortisone
Specifically for CAH Addison’s disease what else must be given apart from the hydrocortisone, fludrocortisons and NACl?
High dose of cortisol to suppress ACTH so sex steroid production is reduced
