Endocrine Weight Loss Thyroid Function and Weight Loss

Question 1

Which thyroid hormone is considered the most metabolically active form at the cellular level?

Accepted Answer

T3 (triiodothyronine)

Answer

T4 (thyroxine)

Answer

Reverse T3 (rT3)

Answer

Thyroglobulin

Question 2

Subclinical hypothyroidism is defined as:

Accepted Answer

Elevated TSH with normal free T4, often asymptomatic

Answer

TSH >10 mIU/L with normal free T4 and symptoms

Answer

Normal TSH with low free T4

Answer

Low TSH with low free T4

Question 3

Which autoantibody is most closely associated with Hashimoto's thyroiditis, the most common cause of hypothyroidism in the US?

Accepted Answer

Anti-thyroid peroxidase antibody (anti-TPO)

Answer

TSH receptor antibody (TRAb)

Answer

Anti-thyroglobulin antibody only

Answer

Anti-smooth muscle antibody

Question 4

A patient with hypothyroidism gains weight primarily because of:

Accepted Answer

Accumulation of myxedema fluid and reduced metabolic rate leading to fat deposition

Answer

Increased fat synthesis stimulated by elevated TSH

Answer

TSH-driven leptin resistance

Answer

Decreased hepatic fat oxidation due to excess thyroglobulin

Question 5

Which thyroid function test is considered the single best screening test for thyroid dysfunction?

Accepted Answer

Thyroid-stimulating hormone (TSH)

Answer

Free T4

Answer

Free T3

Answer

Total T4

Question 6

Levothyroxine (T4) replacement therapy restores metabolic rate and promotes weight loss in hypothyroid patients primarily through which mechanism?

Accepted Answer

Peripheral conversion to T3, which increases mitochondrial uncoupling and basal metabolic rate

Answer

Directly stimulating adipose lipolysis via beta-adrenergic receptors

Answer

Suppressing TSH and thereby reducing myxedema

Answer

Enhancing insulin sensitivity via hepatic PPAR-alpha activation