Flashcards in Endo p. 322-326 Deck (47)
Name the T3 functions—4 B’s:
Basal metabolic rate
When are the levels of TBG decr?
in hepatic failure, steroids usage
How does T3/T4 change the basal metabolic rate?
via Na+/K+-ATPase activity --> incr O2 consumption, RR, body temperature
Which adrenaline receptors in the heart does T4/T3 affect?
incr β1 receptors in heart = incr CO, HR, SV,
What effect does T3/T4 have on glycogen and lipids?
incr glycogenolysis, gluconeogenesis, lipolysis
When are the TBG leves incr?
in pregnancy or OCP use (estrogen incr TBG).
T or F? Propylthiouracil inhibits only peroxidase.
F. inhibits both peroxidase and 5'-deiodinase
Explain the Wolff-Chaikoff effect:
excess iodine temporarily inhibits thyroid peroxidase-->
decr iodine organification--> decr T3/T4 production.
T3 binds --- receptor with ---- affinity than T4.
Methimazole inhibits ---.
coupling of monoiodotyrosine and di-iodotyrosine happens via which enzyme?
T4 is converted to T3 in peripheral tissue by which enzyme?
Which Anions inhibit iodine oxidation?
perchlorate, pertechnetate, thiocyanate, iodide
High-dose dexamethasone suppression test causes what in Cushings dx?
free cortisol suppression
How many mg is administred during High-dose dexamethasone test?
8mg - high dose
Name 3 cause for incr in cortisol?
- Exogenous corticosteroids
- Primary adrenal adenoma, hyperplasia, or carcinoma
- ACTH-secreting pituitary adenoma, paraneoplastic ACTH
Difference between Cushing syndrome and Cushing disease?
ACTH-secreting pituitary adenoma - C. disease
incr Cortisol from variety of conditions - C. syndrome
2 path causing Cushing syndrome?
small cell lung cancer, bronchial carcinoids
Is adrenal tumor an ACTH-independent or dependent Cushing syndrome?
ACTH-independent Cushing syndrome
Is ectopic ACTH secretion an ACTH-independent or dependent Cushing syndrome?
CRH stimulation test helps diagnose which pathology?
Cushing disease (incr ACTH) vs
ectopic ACTH secretion (no incr of ACTH)
What an alternative test used to dx adrenal insufficiency?
Metyrapone stimulation test
metyrapone blocks which process?
11-deoxycortisol --> cortisol
Pt presents w/ sudden onset of massive
hemorrhage and shock. What is the adrenal path?
Primary Acute adrenal insufficiency or Waterhouse-Friderichsen syndrome
Competitive athlete on school break shows signs of adrenal insufficiency, which type is his pathology?
Tertiary: chronic exogenous precipitated by abrupt withdrawal.
skin and mucosal hyperpigmentation is seen in which type of adrenal insuff.? and why?
TB can cause what kind of Adrenal insuff.?
Chronic—aka Addison disease. Due to
adrenal atrophy or destruction by disease
--- is a byproduct of ACTH production from ----.
In which type of Adrenal insuff. is Aldosterone synthesis unaffected?