Adrenocorticosteroids Flashcards
Hormonal Steroids Overview?
• Glucocorticoids
Effects on intermediary metabolism and immune function
• Mineralocorticoids
Principally salt-retaining activity
• Steroids with androgenic and estrogenic activity
Naturally occurring glucocorticoids? MOA?
• Cortisol (Hydrocortisone)
Synthesis & secretion tightly regulated by CNS
Mechanism of Action
• Effects mediated by widely distributed glucocorticoid
receptors
• Steroid-receptor complex enters the nucleus and interacts
with promoters of (and regulates the transcription of) target genes
• Produce tissue-specific responses
Metabolic Effects of Cortisol?
• 95% of hormonal activity is due to cortisol
Metabolic Effects
• Stimulates and is required for gluconeogenesis &
glycogen synthesis (which maintains hepatic glycogen
availability) in fasting state
→ increase serum glucose levels (thus leading to stimulation of insulin release) & inhibiting uptake by muscle cells
• Stimulates lipolysis (leading to fat deposition and
redistribution & increased release of fatty acids & glycerol)
• Stimulates protein catabolism & release of amino acids
Net Result: Maintenance of an adequate glucose
supply to brain (most apparent in fasting state)
Catabolic Effects of Hydrocortisone?
Catabolic Effects
• In addition to protein catabolism, cortisol also has effects in lymphoid and connective tissue, muscle, peripheral fat and skin (wasting occurs at high concentrations)
• Catabolic effects on bone = osteoporosis
• In children = growth retardation
Both are major limitations in long-term treatment with
glucocorticoids.
Immunosuppressive Effects of Cortisol(Hydrocortisone)?
• Effects on leukocytes
• Increased neutrophils (increased influx into blood & decreased migration from blood vessels)
• Decreased lymphocytes (T and B cells),
monocytes, eosinophils and basophils (movement
from vascular bed to lymphoid tissue)
• Vasoconstriction due possibly to suppression of mast cell degranulation
• Decreased histamine release and capillary
permeability
Anti inflammatory effects of Cortisol(hydrocortisone)?
• Inhibition of phospholipase A2
(through induction &
activation of annexin I) which blocks arachidonic acid release (major precursor of prostaglandins).
• Cyclooxygenase-2 synthesis is reduced (through inhibition of NF-kB).
• Induction of MAPK phosphatase I (inhibits MAPK activated proinflammatory signaling pathways).
Other effects of Cortisol (Hydrocortisone)?
• CNS: behavioral changes (insomnia, euphoria leading to depression)
• Increased intracranial pressure: large doses
• Suppression of release of ACTH, growth hormone,
thyroid-stimulating hormone & luteinizing hormone: chronic use
• Peptic Ulcers: Stimulation of gastric acid. Suppression of immune response to H.pylori?
• Increase platelets & RBCs
• Renal function: is impaired with cortisol deficiency
• Development of fetal lungs
Cortisol PK?
- Relatively short duration of action
- Diffuses poorly across skin (unless inflamed)
- Diffuses well across mucous membranes
- Some salt-retaining effects
Name 2 mineralocorticoids? Describe each
Aldosterone
Fludrocortisone
• Aldosterone
Most important mineralocorticoid in humans
• Fludrocortisone
Synthetic corticosteroid. Most commonly prescribed salt retaining
hormone
Name 6 glucocorticoids?
Prednisone Hydrocortisone Dexamethasone Beclomethasone Triamcinolone Methylprednisolone
Name 5 synthetic glucocorticoids?
- Prednisone
- Methylprednisolone
- Dexamethasone
- Beclomethasone
- Triamcinolone
PK of synthetic glucocorticoids?
- Rapidly and completely absorbed orally
- Selected compounds can also be given IV, IM, topically, intra-articularly & by aerosol
- Long t1/2’s
- Reduced salt-retaining effects
Route of administration for glucocorticoids?
Oral?
IM?
Aerosol?
Oral: All can be given orally
IM: Triamcinolone
Aerosol: Beclomethasone
Triamcinolone
ROA glucocorticoids?
IV, IM?
IV,IM: Dexamethasone Hydrocortisone Methylprednisolone Prednisolone
ROA glucocorticoids?
Topical: Beclomethasone Dexamethasone Hydrocortisone Triamcinolone
MOA of Mineralocorticoids?
Mechanism of Action
• Bind to mineralocorticoid receptor
• Drug-receptor complex acts in similar fashion to
glucocorticoid drug-receptor complex
• Major effect of activation of the aldosterone receptor:
• increased expression of Na+ /K+ ATPase
• increased expression of ENaC
Major effects of Mineralocorticoids?
• Natural mineralocorticoid = Aldosterone
• Major role are as salt-retaining hormones
• Under control and regulation of CRH, ACTH and renin angiotensin
system
• Help to control body’s water volume & electrolyte
concentrations (Na+ & K+)
• promote Na+
reabsorption from renal tubule
• promote K+ and H+ excretion