Question
Which of the following hypothalamic nuclei is primarily affected in leptin resistance?
| A. |
Ventromedial nucleus
|
| B. |
Lateral nucleus
|
| C. |
Anterior nucleus
|
| D. |
Arcuate nucleus
|
Show Answer
|
Correct Answer � D
Explanation
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|
– Leptin is secreted by adipose tissue and signals the hypothalamus to suppress appetite &↑ energy use.
– It acts mainly on the arcuate nucleus of the hypothalamus.
– The arcuate nucleus has two main neuron types:
• POMC/CART neurons – suppress appetite (anorexigenic)
• NPY/AgRP neurons – stimulate appetite (orexigenic)
– Leptin activates POMC/CART neurons & inhibits NPY/AgRP neurons, reducing hunger.
– In leptin resistance (e.g., obesity), this regulation blunts despite high leptin → continued appetite &↓ energy expenditure.
Incorrect Options:
A. Ventromedial nucleus – satiety center; responds to leptin secondarily, not primary leptin resistance site.
B. Lateral nucleus – hunger center; stimulated when leptin signaling fails but not directly involved in leptin resistance.
C. Anterior nucleus – controls thermoregulation & parasympathetic output, unrelated to leptin/appetite regulation.
