Term
| What are the actions of Thyroid Hormone? |
|
Definition
Growth and Development -especially Brain, Bones and Teeth
Calorigenic -increased oxygen consumption
Cardiovascular -increased HR and Force of Contraction
Metabolic -maintain homeostasis |
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|
Term
| What converts T4 to the more active T3 form? |
|
Definition
|
|
Term
| What tissues are important for producing T3 to be exported? |
|
Definition
| Liver, Kidney, Thyroid Gland |
|
|
Term
| What tissues have the D2 isoform important for maintaining intracellular T3? |
|
Definition
| Brain, Pituitary, Heart, Skeletal muscle |
|
|
Term
| What produces an inactive form of T3, reverse T3? Where is it found? |
|
Definition
thyronine 5-deiodinase
Placenta, Skin, Brain
(Not 5') |
|
|
Term
| At what point in the pregnancy does the fetus rely on thyroid hormone derived from the maternal circulation? |
|
Definition
|
|
Term
| How are T3 and T4 metabolized? |
|
Definition
| In the Liver through glucuronide conjugation and sulfate conjugation -> excretion through Bile |
|
|
Term
| What is the major carrier of thyroid hormone? |
|
Definition
| Thyroxine Binding Globulin (TBG) |
|
|
Term
| What protein binds T4 2:1? |
|
Definition
|
|
Term
| What transports T4 in CSF? |
|
Definition
|
|
Term
| What is the action of TSH on the Thyroid Gland? |
|
Definition
Immediate -> increased secretion
Later -> iodide uptake, hormone synthesis, proteolysis
Last -> hypertrophy and hyperplasia |
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|
Term
| How does decreased dietary iodine affect the Thyroid? |
|
Definition
| Increased TSH -> thyroid hypertrophy |
|
|
Term
| Where does T3 bind in the nucleus to increase or decrease DNA transcription? |
|
Definition
|
|
Term
| What 2 drugs are used to treat hypothyroidism? |
|
Definition
|
|
Term
| What Thyroid drug is only L-T4? |
|
Definition
|
|
Term
| What Thyroid drug is both T4 and T3? |
|
Definition
|
|
Term
| What can cause Hypothyroidism? |
|
Definition
Hashimoto's thyroiditis
Drug induced
Congenital hypothyroidism
Pituitary disease
(symptoms - myxedema, cretinism, simple goiter) |
|
|
Term
| What can cause Hyperthyroidism? |
|
Definition
Graves Disease
Toxic nodular goiter
(carcinoma) |
|
|
Term
| What does treatment of Hyperthyroidism consist of? |
|
Definition
Surgery
Radioactive iodine Drugs |
|
|
Term
| What 2 drugs are used to treat Hyperthyroidism? |
|
Definition
Propylthiouracil (PTU)
Methimazole |
|
|
Term
| What drugs inhibit iodine organification? |
|
Definition
Propylthiouracil (PTU)
Methimazole |
|
|
Term
| What Thioureylene is preferred in pregnant patients? |
|
Definition
|
|
Term
| Which Thioureylenes is more potent and has a longer half life? |
|
Definition
|
|
Term
| Why should methimazole not be used in pregnant women? |
|
Definition
| Crosses Placenta -> concentrates in fetal thyroid |
|
|
Term
| What is used to treat thyroid storm? |
|
Definition
| Large Doses of Iodine -> inhibit iodine metabolism -> blocks T4 release |
|
|
Term
| What is the Iodinated Contrast Media agent? |
|
Definition
|
|
Term
| What agents have an off label use for hyperthyroidism? |
|
Definition
Iohexol
(inhibit conversion of T4 to T3) |
|
|
Term
| What is the mechanism of action of Iohexol? |
|
Definition
| inhibit peripheral conversion of T4->T3 |
|
|
Term
| What are the two mechanisms of Propylthiouracil (PTU)? |
|
Definition
1) Inhibit iodine organification
(addition to tyrosine on the thyroglobuliln)
2) Inhibit conversion of T4 to T3 |
|
|
Term
| What is used as a permanent treatement for hyperthryoid? |
|
Definition
|
|
Term
| What hyperthyroid drug is only given to adults age 35 and up? |
|
Definition
Radioactive Iodine
(not given to women of childbearing age) |
|
|
Term
| What drugs inhibit conversion of T4 to T3? |
|
Definition
Propylthiouracil (PTU)
(Iodinated Contrast Media)
Iohexol
|
|
|
Term
| What drug is used to treat the thyroid pre-operatively? |
|
Definition
Iodine
(decreases size, vascularity, and fragility of the hyperplastic gland)
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