Which hormone is known for signaling body fat levels to the brain and regulating food intake?

Leptin is a hormone produced by adipose (fat) tissue that plays a crucial role in regulating energy balance by signaling the brain about body fat levels. When fat stores increase, leptin levels rise, which informs the hypothalamus in the brain that the body has sufficient energy reserves. This signaling helps suppress appetite and increases energy expenditure, contributing to the maintenance of body weight.

Leptin's primary function is to help the body regulate food intake and energy usage, making it essential for appetite control and long-term energy homeostasis. Its effectiveness can be influenced by various factors, including insulin sensitivity and inflammation, making it an important focus for research on obesity and metabolic disorders.

Other hormones listed have different roles; for instance, insulin primarily regulates glucose levels in the blood and has effects on fat storage but is not the main hormone dedicated to signaling body fat levels. Ghrelin, often referred to as the "hunger hormone," stimulates appetite and increases food intake, while cortisol is related to stress responses and metabolism but does not directly convey information about body fat levels to the brain.