Endocrine Weight Loss Endocrine System 4 — Questions and Answers
Question 1: Adiponectin levels in obese individuals are typically:
- Elevated, promoting inflammation
- Normal, with no effect on insulin sensitivity
- Low, associated with decreased insulin sensitivity (Correct answer)
- High, causing hypoglycemia
Correct answer: Low, associated with decreased insulin sensitivity
Obesity suppresses adiponectin secretion; low levels are linked to insulin resistance, dyslipidemia, and increased cardiovascular risk.
Question 2: Which region of the hypothalamus contains the primary appetite-regulating neurons that respond to leptin and ghrelin?
- Supraoptic nucleus
- Arcuate nucleus (Correct answer)
- Paraventricular nucleus
- Lateral hypothalamic area
Correct answer: Arcuate nucleus
The arcuate nucleus contains NPY/AgRP neurons (hunger-promoting) and POMC/CART neurons (satiety-promoting) that integrate peripheral hormone signals.
Question 3: A 45-year-old woman reports unexplained weight gain, fatigue, and cold intolerance. The most appropriate initial lab test is:
- Fasting insulin level
- Serum TSH (Correct answer)
- 24-hour urinary cortisol
- IGF-1 level
Correct answer: Serum TSH
TSH is the most sensitive screening test for hypothyroidism, which classically presents with unexplained weight gain, fatigue, and cold intolerance.
Question 4: Brown adipose tissue (BAT) contributes to weight regulation by:
- Storing excess triglycerides for future energy use
- Secreting leptin to suppress appetite
- Generating heat through uncoupled mitochondrial respiration (thermogenesis) (Correct answer)
- Converting glucose directly to muscle glycogen
Correct answer: Generating heat through uncoupled mitochondrial respiration (thermogenesis)
BAT expresses uncoupling protein 1 (UCP1), which dissipates the mitochondrial proton gradient as heat rather than producing ATP.
Question 5: The hormone amylin, co-secreted with insulin from pancreatic beta cells, aids weight management by:
- Stimulating glucagon release to mobilize fat
- Slowing gastric emptying and promoting satiety (Correct answer)
- Increasing leptin receptor sensitivity
- Activating lipoprotein lipase in adipocytes
Correct answer: Slowing gastric emptying and promoting satiety
Amylin slows gastric emptying, suppresses postprandial glucagon, and acts centrally to reduce food intake.
Question 6: Which condition is characterized by excessive cortisol production from an adrenal or pituitary tumor and causes significant obesity?
- Addison's disease
- Cushing's syndrome (Correct answer)
- Conn's syndrome
- Sheehan's syndrome
Correct answer: Cushing's syndrome
Cushing's syndrome results from chronic cortisol excess and causes central obesity, hypertension, glucose intolerance, and skin changes.
Question 7: Sex hormone changes after menopause contribute to weight gain primarily by:
- Dramatically increasing appetite via ghrelin surges
- Causing insulin resistance and shifting fat distribution to the abdomen (Correct answer)
- Reducing thyroid hormone conversion from T4 to T3
- Elevating growth hormone levels that increase fat storage
Correct answer: Causing insulin resistance and shifting fat distribution to the abdomen
Estrogen decline after menopause reduces insulin sensitivity and promotes fat redistribution from the hips and thighs to the visceral compartment.
Endocrine Weight Loss Endocrine System 4
Adiponectin levels in obese individuals are typically: