Midterm--Dr. Boothe Flashcards
The core structure of all steroids? Its importance?
pregnane nucleus
lipid soluble so steroids can penetrate cell membranes
What chemical structure changes are required for a corticosteroid to have glucocorticoid activity
A C4=C5 double bond
Ketone on C3 (=O)
Concerning corticosteroids, what modifications can be made to:
1) increase glucocorticoid activity
2) prevent mineralocorticoid activity
1) add double bond at C1=C2
2) adding methyl group to C16
**These are the 2 things you would undo to increase mineralocorticoid activity
Benefits of a fluorine group?
increases potency and tissue penetration
*in both GC and MC
How does GC potency affect:
1) dose
2) MC activity
3) side effects
1) increases potency lowers dose requirements
2) increasing potency LOWERS MC activity
3) increasing potency is associated with an increase in assoc. side effects
The major target organ for:
1) glucocorticoids
2) mineralocorticoids
1) Liver
2) kidney (distal and collecting tubules)
How do GCs and MCs differ in their impact on the patient’s hydration status?
MCs work at the level of the kidney to retain Na/water and excrete K & H+
GCs have anti-ADH effect, leading to water loss (stimulates centrally-mediated increased water consumption)
Why are GCs useful in situations of hypercalcemia?
because they act to deplete the body of Ca
*prevent GI absorption, prevent mobilization from bone, and increase urinary excretion
Describe 3 permissive effects corticosteroids can have on the body
1) alpha-mediated peripheral vasoconstriction
2) increased CO (beta 1)
3) increased oxygenation–bronchodilation (beta 2)
**permissive to the body’s adrenergic signals
Name 2 ways glucocorticoids can impact/prevent activation of the arachadonic acid pathway?
1) the prevent mast cell degranulation (histamine and seratonin aren’t released–>no damage to cell membranes
2) regulate the production of lipocortin which is inhibitory to phospholipase (no phospholipase= no cell membrane destruction)
What is the standard physiologic dose?
0.25mg/kg
Describe two inhibitory effects of glucocorticoids on the immune system
1) decreases macrophage antigen processing
2) decreases clonal expansion of T cells
The addition of _____ alters absorption of parenterally administered glucocorticoids
R groups (ester-salts)
Which esters cause:
1) very rapid release (rapid onset, short duration)
2) slow release
1) succinate
2) acetate (“depo” preparations) these can’t go IV
Which spp. require prednisolone? why?
Horses and cats
don’t absorb prednisone well
