Exam II Endocrine Pharm Flashcards
Thyroxin (T4) and triiodothyronine (T3) is synthesized from __________.
Control of these hormones are determined by _________________
- Iodine
- Negative feedback loop
Lack of iodine in the diet causes what?
Excessive secretion of TSH, resulting in thyroid hypertrophy–> Goiter
Primary hypo/hyperthyroidism =
Disease of thyroid gland
Secondary hypo/hyperthyroidism =
Disease of pituitary or hypothalamus gland
What is the precursor to making thyroid hormones T4 and T3?
L-tyrosine
-T4 and T3 are iodinated derivates of tyrosine.
Iodine is required for the synthesis of _____________. With out iodine, buildup of TH precursor, resulting in _________.
Americans obtain iodine from __________
- Thyroid hormones
- Goiter
- Iodized salt
Thyroglobulin is NEVER _____________
secreted into the bloodstream
How is TH synthesized within the thyroid gland ?
1) It is taken up by the thyroid cuboidal epi cells at the basement membrane.
2) Synthesis of polypeptide chain within the ER and completed in the golgi.
3) Newly synthesized thyroglobulin is transported to cell surface in vesicles.
Coupling of todotyrosyl precursors (diiodotyrosine and moneydotyrosine) result in ___________________.
Subsequent storage of iodinized thyroglobulin is in the _______.
Thyroglobulin is retrieved via ___________into small vesicles.
- iodination of thereglobulin
- lumen
- micropinocytosis
Lysosomes fuse with vesicles resulting in what?
Proteolysis of thyroglobulin and release of iodinated amino acids (T3) and (T4)
T4 and T3 exit the thyroid gland and into the _______.
Diiodotyrosine and moniodotyrosine undergo ________________, allowing for _________________
-blood
deiodination
-recirculation of iodine
What are the 2 synthetic thyroid preparations made by industry?
1) Sodium levothyroxine
T4= Synthroid, Levoxyl
2) Sodium liothyronine (T3 = Cytomel)
Sodium levothyroxine is the __________ for most cases of hypothyroidism.
_______ dose concentrations available.
__________ is the most widely sold brand name.
- Preferred
- 11
- Synthroid
Sodium liothyronine, oral absorption is more _____________
erratic (why this agent is not the preferred drug)
Sodium levothyroxine (T4) is used for what? What is the adult dose?
Use: replacement or supplement therapy in hypothyroidism
The adult dose: 100 to 200 micrograms daily (usually taken in the morning on empty stomach)
What is the mechanism of Sodium levothyroxine (T4) ?
1) Affects DNA transcription and stimulates protein synthesis
2) Promotes gluconeogenesis
3) Mobilizes glycogen stores
4) Increases basal metabolic rate
What are important adverse effects of Sodium levothyroxine (T4) ?
(indicases overdose= hyperthyroidism)
1) Palpitations, tachycardia
2) Nervousness, sweating
3) Increased appetite
4) Weight loss
What are the drugs used to TX Hyperthyroidism (anti-thyroid drugs?)
1) Propylthiouracil
2) Iodides
3) Methimazole (Tapazole)
4) Radioactive Iodide I 131
Propylthiouracil:
is a __________ drug. Nicknamed___________.
Used for _____________ treatment of hyperthyroidism in ______________ or _____________ therapy; management of _____________
- Canadian
- PTU
- Palliative
- preparation for surgery
- radioactive iodine
- thyrotoxic
What is the mechanism for Propylthiouracil?
Blocks iodination reaction (blocks oxidation of iodine) in thyroid gland; blocks synthesis of T4 and T3.
What is the side effects for Propylthiouracil?
1) Skin rash
2) nausea
3) agranulocytosis
Iodides are saturated solution of ____________.
Mechanism of action is ____________
Used in conjunction with ______________ to prepare patients for surgery.
- Potassium iodide
- Not clear: probably reduces secretion of thyroid hormone.
- propylthiouracil
What is the use of Methimazole (Tapazole)?
1) Palliative treatment of hyperthyroidism, return the patient to a normal metabolic state prior to thyroidectom.
2) control thyrotoxic crisis that may accompany thyroidectomy.
What is the mechanism of Methimazole (Tapazole)?
1) Blocks iodination reaction (blocks oxidation of iodine) in thyroid gland
2) blocks iodine’s ability to combine with tyrosine to form T3 and T4.