Exam 2- HPA & Thyroid Flashcards
1
Q
Somatostatin analogs
A
- Growth hormone antagonist
- Inhibits release of GH, glucagon, insulin, and gastrin
- Octreotide = long acting
2
Q
Dopamine D2 receptor agonists
A
- Growth hormone antagonist
- Bromocriptine
- Effective at inhibiting prolactin release (more than GH) but high doses have some efficacy in small GH secreting tumors
3
Q
Major secretory product of the thyroid gland
A
T4 (Thyroxine)
4
Q
Major active product of the thyroid gland
A
T3 (Tri-iodothyroine)
5
Q
Most of the thyroid hormones are transported this way
A
Bound to thyroxine-binding globin (TBG), prealbumin, or albumin
6
Q
These thyroid hormones are active
A
Only free
7
Q
Problem location- (TRH ↑) TSH ↑, T3-T4 ↓
A
Thyroid hypofunction
8
Q
Problem location- (TRH ↑) TSH ↓, T3-T4 ↓
A
Pituitary hypofunction
9
Q
Problem location- (TRH ↓) TSH ↓, T3-T4 ↑
A
Thyroid hyperfunction
10
Q
Problem location- (TRH ↓) TSH ↑, T3-T4 ↑
A
Pituitary hyperfunction
11
Q
Levothyroxine
A
- Thyroid agent
- Synthetic T4
- Used in hypothyroidism
- AE: nervousness, heat intolerance, palpitation/tachycardia, weight loss
12
Q
Radioactive iodine
A
- Antithyroid agent
- I-131
- Used for the treatment of thyrotoxicosis
- Rapidly absorbed, concentrated in the thyroid, and incorporated into storage follicles
- Crosses the placenta and excreted in breast milk (contraindicated)
13
Q
Thioamides
A
- Antithyroid agents
- Methimazole & Propylthiouracil
- Propylthiouracil inhibits conversion of T4 to T3 so brings level down faster
- Inhibit thyroid peroxidase-catalyzed reactions blocking iodine organification (prevents binding of iodide to tyrosine)
- AE: Severe hepatitis with PTU and agranulocytosis (infrequent but potentially fatal)
14
Q
Potassium iodide
A
- Iodide (antithyroid agent)
- Blocks release of T4 and T3 and inhibits iodine organification
- Reduces size and vascularity of hyperplastic gland (useful as preoperative prep for surgery)
- Use: Must be given AFTER a thioamide to prevent iodine from being used in new hormone synthesis; given a week after RAI, normalizes thyroid function earlier than RAI alone; given to protect thyroid from radioactive iodine fallout (uptake of RAI is inversely proportional to serum concentration of stable iodine)
- Cross placenta and can cause fetal goiter
15
Q
Beta Blockers
A
- Useful in controlling tachycardia and other cardiac abnormalities of severe thyrotoxicosis
- Propranolol also inhibits peripheral conversion of T4 to T3
