Endocrine Weight Loss Endocrine Disorders 3 — Questions and Answers
Question 1: Which enzyme converts inactive cortisone to active cortisol within adipose tissue, potentially promoting local fat accumulation?
- Aromatase
- 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) (Correct answer)
- Lipoprotein lipase
- Hormone-sensitive lipase
Correct answer: 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1)
11β-HSD1 converts inactive cortisone to active cortisol within adipose tissue, and its overactivity in visceral fat contributes to central obesity.
Question 2: A patient with hypothyroidism is started on levothyroxine. How long should clinicians wait before rechecking TSH to assess dose adequacy?
- 1–2 days
- 1–2 weeks
- 4–6 weeks (Correct answer)
- 6 months
Correct answer: 4–6 weeks
TSH levels take 4–6 weeks to stabilize after a levothyroxine dose change, reflecting the long half-life of T4 and pituitary feedback.
Question 3: Which type of diabetes insipidus can cause weight gain through compulsive fluid intake leading to hyponatremia and secondary hormonal changes?
- Central diabetes insipidus
- Nephrogenic diabetes insipidus
- Primary polydipsia (psychogenic) (Correct answer)
- Gestational diabetes insipidus
Correct answer: Primary polydipsia (psychogenic)
Primary polydipsia involves compulsive water intake not driven by ADH deficiency, which can cause dilutional hyponatremia and disrupt normal satiety signaling.
Question 4: Insulin resistance in obesity is best described as a state where:
- The pancreas produces less insulin than needed
- Target cells fail to respond normally to circulating insulin (Correct answer)
- Insulin is degraded too quickly in the bloodstream
- The liver produces excessive glucagon
Correct answer: Target cells fail to respond normally to circulating insulin
Insulin resistance means that muscle, liver, and fat cells do not respond effectively to insulin, requiring the pancreas to secrete more to maintain glucose control.
Question 5: Which pituitary tumor can cause weight gain by disrupting hypothalamic satiety centers due to its anatomical location?
- Prolactinoma
- Corticotroph adenoma (ACTH-secreting)
- Craniopharyngioma (Correct answer)
- Growth hormone-secreting adenoma
Correct answer: Craniopharyngioma
Craniopharyngiomas arise near the hypothalamus and can damage satiety centers, causing severe hypothalamic obesity that is notoriously difficult to treat.
Question 6: A man with hypogonadism and low testosterone is most likely to experience which metabolic consequence?
- Decreased visceral fat and increased muscle
- Increased lean mass and bone density
- Increased visceral fat, decreased muscle mass, and insulin resistance (Correct answer)
- Hyperthyroidism and weight loss
Correct answer: Increased visceral fat, decreased muscle mass, and insulin resistance
Testosterone deficiency leads to increased visceral adiposity, loss of lean muscle mass, and worsening insulin resistance, creating a cycle of metabolic dysfunction.
Question 7: Which condition is characterized by episodic hypertension, diaphoresis, headaches, and weight loss due to excess catecholamine secretion?
- Primary hyperaldosteronism
- Cushing's syndrome
- Pheochromocytoma (Correct answer)
- Graves' disease
Correct answer: Pheochromocytoma
Pheochromocytoma is an adrenal medullary tumor that secretes excess catecholamines, causing episodic hypertension, sweating, headaches, and paradoxical weight loss.
Endocrine Weight Loss Endocrine Disorders 3
Which enzyme converts inactive cortisone to active cortisol within adipose tissue, potentially promoting local fat accumulation?