Glucocorticoids and the Stress Response Flashcards
How has cortisol been linked to depression?
50% of depressed patients have elevated cortisol
Dexamethasone suppression test abnormal in depressed patients
Depression is a symptom of Cushing’s (high cortisol) and Addisons (low cortisol)
What is the dexamethasone suppression test?
People usually have high cortisol in the morning
If given dexamethasone bolus, HPA negative feedback turns off cortisol production, so no cortisol surge in morning
When is cortisol released?
High in morning
Low during night
Describe the 2 proposed mechanisms that glucocorticoids affect gene transcription
Bind to gene for anti-inflammatory protein, driving its production
Bind to TF binding site for cytokines and inhibit production of inflammatory protein
Why is dexamethsone one of the most commonly used glucocorticoids?
High potency
Long half life
Give 3 immunosupressive actions of glucocorticoids
Inhibit interleukin production
Suppress B cells making them express less IL-2R and IL-2
Down regulate Fc receptors on macrophage reducing phagocytosis
Why must you be careful when taking a patient off steroids?
Use can suppress CRH and ACTH
Need to wein off so there is not withdrawal
Which immune cells cause T1D?
T cells
