Adrenocortical Steroids Flashcards
secretes glucocorticoids
zona fasciculata
secretes mineralocorticoids
zona glomerulosa
secretes the androgens
zona reticularis
secretes the catecholamines (norepinephrine, epi)
medulla
principal endogenous glucocorticoid substance produced by zona fasciculata is the
cortisol
cortisol secretion is regulated by
ACTH from the anterior pituitary
circadian rhythm pattern
it peaks early morning (before waking up) and after meals
Main mineralocorticoid is _______ which is regulated by Renin- Angiotensin system in response to sodium level and ECF.
aldosterone
Main androgen secreted is ____
Dehydroepiandrosterone (DHEA)
oral absorption of glucocorticoids
Rapidly and completely absorbed
Water soluble esters
via IV administration ➡️ high concentrations in tissue fluids
Insoluble esters
via IM administration ➡️ slowly absorbed; more prolonged effects
Local administration of glucocorticoids
also absorbed (some systemic)
same pharmacokinetic pathways as glucorticoids given systemically
TRANSPORT of glucocorticoids
Protein bound
- 90% to Corticosteroid-Binding Globulin (CBG)
- albumin (loosely bound)]
are largely bound to albumin rather than CBG.
Synthetic corticosteroids such as dexamethasone
CBG is increased in
pregnancy, with estrogen administration and in hyperthyroidism
20% of cortisol is converted to this bio inactive form
cortisone
more resistant to metabolism➡️longer acting
synthetic congeners
urine excretion of glucocorticoids
a. (2/3) conjugates of glucuronide and sulfate
b. (1/3) dihydroxy ketone metabolites
a gauge of the response of cortisol to ACTH stimulation/repression when exogenous glucocorticoids are given
17-hydroxysteroids
glucocorticoid interaction: responsible for the metabolic effects
promoters on target genes
glucocorticoid interaction: responsible for the anti-inflammatory effects
repressors on target genes
glucocorticoid interaction: regulate proinflammatory cytokines, growth factors, etc (delayed onset of effects)
transcription factors
glucocorticoid classification based on
- Duration of action
- RELATIVE potencies on
a. Sodium retention
b. effects on CHO metabolism
c. anti-inflammatory effects
potency to affect glucose metabolism closely parallel their potency as an anti-inflammatory
glucocorticoids
short acting glucocorticoids
Hydrocortisone
Cortisone
intermediate acting glucocorticoids
Prednisone
Prednisolone
Methylprednisolone
Triamcinolone
long acting glucocorticoids
Dexamethasone
Betamethasone
equal anti inflamm and salt retaining activity at 25 mg
CORTISONE
equal salt retaining activity and anti inflammatory activity at 20mg
HYDROCORTISONE
intermediate acting GC with no salt retaining activity at 4mg
TRIAMCINOLONE