Control of Appetite Quiz

See Suppressing Appetite. Option C is correct because leptin is a hormone released by adipocytes (fat cells), and the amount in the blood reflects the amount of fat the body is carrying. It travels to the hypothalamus and binds leptin receptors in the arcuate nucleus (the hypothalamic cluster of appetite-controlling neurones). There it promotes the appetite-suppressing peptides (such as pro-opiomelanocortin) and reduces the appetite-stimulating ones (neuropeptide Y and agouti-related peptide). The overall effect is that appetite falls and food intake is reduced. This forms a negative feedback loop in which larger fat stores lead to more leptin, lower appetite and eventually less fat, so leptin is a long-term regulator of energy balance (the balance between the energy taken in and the energy used). Peptide YY, from the gut, is the matching short-term signal that suppresses appetite at the end of a meal. A helpful phrase to hold on to is that leptin comes from the fat cells and says "you have enough stored".

• Source: leptin is released by adipocytes (fat cells) in proportion to the amount of body fat.
• Action: it binds leptin receptors in the arcuate nucleus of the hypothalamus.
• Effect: it promotes pro-opiomelanocortin and reduces neuropeptide Y and agouti-related peptide, so appetite falls.
• Timescale: leptin is a long-term regulator of energy balance, unlike the short-term gut signals.