Endocrine: Steroids Flashcards
What are the two steroids of interest released by the adrenal gland?
Aldosterone and cortisol
Where is the adrenal gland situated?
Above the kidney
What part of the adrenal gland is aldosterone released form?
zona glomerulosa
What part of the adrenal gland is cortisol released form?
zone fasicularis
What is the action of aldosterone?
Regulates salt and water absorption - increases salt and water retention
= indirect effect on blood pressure, raises bp.
How are the actions of aldosterone inhibited?
ACE inhibitors:
Inhibits conversion of angiotensin which prevents the stimulation of aldosterone which prevents the retention of salt and water.
Inhibiting the conversion of angiotensin also prevents vasoconstriction and therefore an increase in BP. (since angiotensin 2 is a potent VC)
Why might ACE inhibitors not be used? What is used instead?
ACE inhibitors have side effects:
Angio-oedema
Cough
Oral lichenoid
Use AT2 blockers instead.
When are larger amounts of cortisol produced?
At night, when the body is under physical and psychological stress or fighting infection.
What are the physiological effects of cortisol?
Antagonistic to insulin = type 2 diabetes
Suppress the immune system
Inhibits bone synthesis
Raises BP
List examples of therapeutic steroids and their potency in comparison to cortisol.
Hydrocortisone (1x)
Prednisolone (4x)
Dexamethasone (25x)
Beclamethasone (30x) used in asthma
What are the negative effects of therapeutic steroid use?
Type 2 diabetes Osteoporosis Gastic ulceration Hypertension Thinning of the skin Infection risk
What regulates cortisol?
ACTH produced in the anterior pituitary regulates cortisol.
What effect does cortisol in large quantities have?
Acts as aldosterone - increases salt and water retention = raises circulating volume = raises BP
What is cushing’s syndrome?
Hyperfunction of cortisol
What is a primary cause of cushing’s syndrome?
Adrenal tumours
In terms of steroid levels; how do you diagnose primary cushing’s syndrome?
Low ACTH
High cortisol