Adrenocortical Steroids Flashcards
For what purpose are glucocorticoids used as drugs?
suppression of immune system and inflammatory response
Describe the hypothalamic-pituitary-adrenal axis.
hypothalamus produces corticotropin releasing hormone (CRH); signals corticotrophs in the anterior pituitary to release adrenocorticotropin (ACTH); signals adrenal cortex to produce glucocorticoids, androgens, mineralocorticoids
What provides negative feedback to this axis?
glucocorticoid levels
What are the main steroids produced by the adrenal cortex?
cortisol
aldosterone
DHEA (dehydroepiandrosterone)
All steroid hormones are derived from what?
cholesterol
What is the rate-limiting step of steroid production?
conversion of cholesterol to pregnenolone
actions of glucocorticoids (cortisol)
increase blood glucose, opposite effect of insulin
- -increase protein breakdown
- -increase lipolysis and cause fat redistribution
- -increase gluconeogenesis and glycogen synthesis
- -decrease glucose utilization by muscle
What is the action of mineralocorticoids?
ex: aldosterone
target the kidney to affect water and electrolyte balance; increase Na reabsorption, increase K/H excretion
*loss would be an acute and life-threatening situation
What is CAH-1?
congenital adrenal hyperplasia type 1; loss of enzyme CYP21A2; progesterone not converted; **decreased mineralocorticoid; lack of cortisol doesn’t inhibit axis so ACTH is continually stimulating the adrenal cortex; increased androgens into the system
What is CAH-2?
congenital adrenal hyperplasia type 2; loss of expression of CYP11B1; **excess mineralocorticoid & increased precursors; lack of cortisol also increases androgens
What is primary aldosteronism?
d/t adrenal adenoma, hyperplastic adrenals, malignant tumors; excess mineralocorticoid w/out excess GC
What is Cushing’s syndrome?
increased cortisol production d/t adrenal defect, increased ACTH secretion from pituitary or from other tumorous tissues
results: hyperglycemia, HTN, fat redistribution, muscle wasting
