Which hormone secreted by fat cells signals satiety and suppresses appetite?

• A. Ghrelin
• B. Adiponectin
• C. Leptin
• D. Insulin

Answer: (C)

The main idea here is how fat tissue communicates energy status to the brain to regulate hunger. Leptin is a hormone produced by fat cells whose level rises as fat stores increase. It travels to the hypothalamus and binds receptors that dampen appetite and can boost energy expenditure. This signaling helps the body match food intake to its energy reserves over the long term. When leptin signaling works well, higher fat stores lead to reduced hunger; when it doesn’t, as in leptin resistance, this feedback can fail.

Ghrelin, on the other hand, is released by the stomach and increases appetite, especially before meals. Adiponectin is another fat-cell hormone, but it mainly influences insulin sensitivity and inflammation rather than directly signaling satiety. Insulin is produced by the pancreas and also communicates energy status to the brain, but it is not secreted by fat cells.