181b - Pituitary/Adrenal/Thyroid Pharm Flashcards
Describe the signaling pathway activated by the growth hormone receptor
JAK tyrosine kinase phosphorylates STAT5
- > Homodimerization
- > Effects gene transcription
Which hormone can be used to induce labor?
Oxytocin
All of the following are symptoms or results of excessive thyroid hormone, except
- elevated heart rate
- decreased TSH
- increased glycogenolysis
- increased basal metabolic rate
- increased cholesterol
e. increased cholesterol
* Thyroid hormone lowers cholesterol*
What is the predominant thyroid hormone receptor in the hypothalamus?
What is are the effects?
TR-Beta2
Important for negative feedback
What is the effect of thyroid hormone on glycogenoloysis?
Thyroid hormone increases glycogenlolysis
Why is it important to taper patinets off of exogenous glucocorticoids after weeks of use?
Prevent secondary hypo-cortisolism
- Exogenous glucocorticoids suppress ACTH
- Need to taper to allow time for upregulation of ACTH production
What is the 1st line treatment for central diabetes insipidus?
What abour peripheral?
- Central: Desmopressin
-
Peripheral: Thiazides, NSAIDs, amiloride
- If pt is taking lithium, give amiloride
- Thiazides and NSAIDs will increase serum Li levels (amiloride will decrease - need to dose adjust, but less risk of toxicity)
Which drugs inhibit 5’-deiodinase?
Propylthiouracil (PTU)
Propanolol (weak inhibitor)
Inhibiting 5’-deiodinase = inhibiting peripheral conversion of T4 to T3
What signaling pathway is activated by the oxytocin receptor?
What is the effect?
Gq -> PLC -> Ca2+
-> Smooth muscle contraction, protaglandin and leukotriene release
List 2 IGF-1 agonists
Mecasermin
Mecasermin rinfabate (longer 1/2 life)
Mecasermin rinfabate contase serum binding protein IGFBP-3, which gives it a longer half life
c. Dexamethasone test is used to determine the etiology of adrenal hyperfunction
- Addison’s disease is treated with glucocorticoids and mineralcorticoids - primary adrenal insufficiency
- 11-hydroxylase deficiency is treated wtih glucocorticoids only
- Steroid withdrawal syndrome results from chronic reduction of ACTH secretion
Prednisone has the advantage over hydrocortisone that prednisone
- is less likely to increase blood glucose
- doesn’t suppress the immune response
- has a longer duration of action
- is orally effective
- has greater glucocorticoid/mineralocorticoid activity
e. has greater glucocorticoid/mineralocorticoid activity
=> prednisone has more anti-inflammatory effects, causes less hypertension
What are the stimuli for endogenous vasopressin (ADH) release? (2)
Low blood pressure
Hypertonicity
Even if hypotonic, ADH will be released to preserve blood volume at the expense of osmolarity
How should dosing of methimazole be changed in pregnant patients?
Dose should be lowered
- Also, contraindicated in the 1st trimester (use PTU instead)
Which agents can be used to inhibit glucocortidoid synthesis? (4)
-
Metyrapone
- –| 11-hydroxylase
-
Ketokonazole
- –| 17-alpha hydroxylase, desmolase
- (Also –| 17,20 lyase to block testosterone synth)
-
Aminoglutethimide
- –| cholesterol side chain cleavage
-
Mitotane
- Toxic
Mifepristone can also be used as tx for hyper-cortisolism MOA = glucocortidoid receptor antagonist
21-hydroxylase deficiency
- Cortisol:
- Mineralcorticoids:
- Androgens:
- Cortisol: None
- Mineralcorticoids: None
- Androgens: High
17-hydroxylase deficiency
- Cortisol:
- Mineralcorticoids:
- Androgens:
- Cortisol: None
- Mineralcorticoids: High
- Androgens: Low
What is the MOA of pegvisomant?
Growth hormone receptor antogonist
Allows receptor dimerization, but blocks downstream signaling
Use to treat acromegaly