Glucocorticoids, Mineralcorticoids, and Adrenocortical Antagonists Flashcards
What is the known ACTH analog?
Synthetic ACTH (AA 1-24) Cosyntropin (Cortrosyn)
What glucocorticoid analogs are on the market?
Cortisol=hydrocortisone (Cortef, Hydrocortone)
Prednisone (Deltasone)
Prednisolone (Delta- Cortef)
Methlprednisolone (Medrol)
Dexamethasone (Decadron)
Budesonide Inhalation (Pulmicort)
What are the mineralcorticoid analogs?
Fludrocortisone (Florinef)
What are the mineralcorticoid antagonists?
Spironolactone and Eplernone
What are some inhibitors of adrenocortical steroid synthesis or action?
Amingogluthemide (Cytadren)
Ketoconazole (Nizoral)
What is ACTH made from?
proopiomelanocortin (POMC) (which is cleaved to form ACTH, MSH and endorphins)
Briefly describe the ACTH axis
Circadian rhythm and stress (sometimes in the form of immune factors like IL-1/2/6, TNFa) signal release of CRH from the hypothalamus, which stimulates release of ACTH from the anterior pituitary, and subsequent adrenal cortex hormone production
NOTE: It makes sense that inflammatory factors like IL-1 would stimulate ACTH and CRH given that cortisol inhibits their production via binding to white cells
Which is released from the adrenal cortex in large quantites, cortisol or aldosterone?
Cortisol is released at 10 mg/day and aldosterone is produced at 0.125 mg/day (100x difference).
What enzyme deactivates cortisol in cells where aldosterone acts to cortisone (kidney, colon, and salivary glands)?
11B-HSD type II (thus cortisol cannot bind to aldosterone receptors!)
In addition to direct effects, glucocorticoids also have permissive effects. What does this mean?
ex. epi and nor have minor effects on lipolysis in the absence of glucocorticoids, but much greater in their presence (this ex. is due to increased synthesis of lipases) due to upregulation of adrenergic receptors by cortisol
Do corticosteroids act quickly?
Most of the effects of steroid hormones are via upregulation of DNA transcription so they are delayed several hours. However, a few effects are immediate and are mediated by membrane receptors
What are the effects of glucocorticoids on blood glucose?
They protect the brain during starvation by keeping blood glucose elevated via increased gluconeogenesis and glycogenolysis in the liver.
Also, in the periphery glucosteroids decrease glucose uptake, increase proteolysis (to provide AAs for gluconeogenesis) and lipolysis (gycerol for gluconeogenesis)
How do glucocorticoids affect lipids?
In addition to promoting lipolysis, cortisol promotes redistribution of body fat and
athey also have permissive effects on other agents such as GH and b-adrenergic receptor agonists (iso and nor) in increasing lipolysis in adipose tissue.
An excess of either glucocorticoids or mineralcorticoids will affect muscle how?
impair muscle function (primary aldosteronism causes muscle weakness via hypokalemia and glucocorticoids via increased proteolysis and Ca2+ loss)
How do glucocorticoids affect the brain?
It results in euphoria and feelings of well-being, high motor activity, insomnia, and restlessness
(in addison’s disease, you might see apathy, depression, and irritability)
How do glucocorticoids affect the inflammatory process?
They are anti-inflammatory and inhibit:
- phospholipase A2 action via lipocortin
- production and release of cytokines (especially IL-1, IL-2, IL-6, and TNFa)
- histamine and serotonin release
What is the half-life of cortisol, hydrocortisone, or cortisone acetate?
short (all of these can be given PO, IM, or IV)
What is the half-life of prednisone, prednisolone, or methylprednisolone?
intermediate (note prednisone can only be given PO, prednisolone IM and IV, and methlprednisolone IM, IV, and PO)
What are the long acting glucocorticoids?
Dexamethasone (IM, PO, topical, IV) and triamcinolone (PO, topical)
What are the AEs of glucocorticoid therapy?
- suppression of ACTH and TSH production from the pituitary (recovery can take weeks to months)
- osteoporosis
- induced diabetes
- peptic ulcers
- arousal and euphoria, followed by depression and insomnia commonly