Endo-Repro L14 Thyroid drugs

Question 1

Thyroid hormone synthesis and secretion: (8 steps)

Answer 1

1. Iodide building block using ATP Na+ iodide symporter – taken into cell.
2. Pendride → Cl- iodide transported – colloid.
3. Uptake of iodide
4. Iodination and coupling
5. Endocytosis and secretion
6. Vesicle fuses w/ lysosomes
7. Breakdown of protein → T3/4 released
8. MIt/DIT taken up by colloid to reuse

Question 2

Regulation of thyroid hormone release:

Answer 2

1. Cold, trauma and stress input into the hypothalamus.
2. Hypothalamus releases TRH which stimulates the anterior pituitary
3. The Anterior pituitary releases TSH which stimulates the thyroid to make and release T3/4
   a. Binds via GPCR
4. T3/4 negatively feedback to the pituitary

Question 3

Actions of thyroid hormone:

Answer 3

1. Calorigenesis → degeneration of heat
2. Increased Metabolism → production and use of energy
3. Growth and maturation
4. Cardiovascular effects

Question 4

Hypothyroidism: Causes

Answer 4

Primary → autoimmune thyroiditis or iodiopathic atrophy.
Secondary → affecting anterior pituitary
Tertiary → affecting the hypothalamus

Iodine defiency → diet related → increased release of TSH

Natural goitrogens → interfere with iodine uptake.

Question 5

Hypothyroidism: Symptoms

Answer 5

Cretinism in young

Myxoedema in adult:

1. Lethargy
2. Cold intolerant
3. Weight gain
4. Cold, raw skin
5. Husky voice
6. Muscle weakness

Question 6

Hypothyroidism:Diagnosis → Can measure

Answer 6

1. Increased levels of TSH
2. Thyroglobulin (TgAB) antibodies (lymphocytic thyroidism)
3. Reduced T3/4 levels (can’t always measure)
4. Hypercholestraemia

Question 7

Hypothyroidism: Treatment – mainly replacement

Answer 7

• Levothyroxine sodium, T4 → given orally, standard treatment.
• Tri-iodothyronine, liothyronine, T3 (more difficult to manage as has quick high spikes)
• Iodide (sodium or potassium iodide

Question 8

Hyperthyroidism (Thyrotoxicosis): Common Causes

Answer 8

• Grave’s disease

* Tumours of the thyroid gland

Question 9

Hyperthyroidism (Thyrotoxicosis): Symptoms

Answer 9

Nervousness
Irritability
Increased perspiration
Heart racing
Hand tremors
Anxiety
Difficulty sleeping
Thinning of the skin
Fine brittle hair
Muscular weakness

Question 10

Hyperthyroidism (Thyrotoxicosis): Diagnosis

Answer 10

Symptoms of hyperthyroidism
Mass at base of neck
Increased levels of T4
Decreased levels of TSH

Question 11

Hyperthyroidism (Thyrotoxicosis): Treatment

Answer 11

Drugs that inhibit T3/4 secretion
High disease of iodide
Thyroidectomy
Beta-adrenergic receptor antagonist (propranolol)
Radio iodine

Question 12

Hyperthyroidism (Thyrotoxicosis): Drugs that inhibit T3/4 secretion

Answer 12

Thiureylenes
Carbimazole
Methimazole
Felimazole

Question 13

High disease of iodide

Answer 13

Reduced synthesis and release of thyroid hormones (unsure why)

Question 14

Radio iodine

Answer 14

Concentrated in thyroid gland destroys follicle cells → beta radiation

Question 15

Beta-adrenergic receptor antagonist (propranolol)

Answer 15

Doesn’t change hormone concentration but blocks effect on here.

Question 16

Side effects of hyperthyroid drugs

Answer 16

Hypothyroidism
Poor appetite
Vomiting
Lethargy
Reduced white cells and platelet
Liver disorders