Final answer:
Leptin activates POMC neurons and inhibits AgRP/NPY neurons, helping to suppress appetite and promote energy expenditure. It also plays a role in reproductive functions by influencing the synthesis of GnRH and gonadotropins.
Step-by-step explanation:
Leptin is a protein hormone secreted by adipose tissues in response to food consumption that promotes satiety. The correct answer to the student's question is that Leptin activates POMC neurons and inhibits AgRP/NPY neurons, which is option B) Leptin activates POMC neurons and inhibits AgRP/NPY neurons. When leptin levels rise, it binds to receptors in the brain, particularly in the hypothalamus. It increases the activity of Proopiomelanocortin (POMC) neurons, which encourage satiety and energy expenditure, while simultaneously inhibiting the activity of Agouti-related peptide (AgRP) and Neuropeptide Y (NPY) neurons, which would otherwise stimulate hunger. This dual mechanism helps to decrease appetite and food intake, leading to increased energy expenditure and reduced body weight. Leptin also plays a critical role in reproductive functions, as it is necessary for the synthesis of gonadotropin-releasing hormone (GnRH) and gonadotropins, influencing the onset of puberty and fertility levels.