Which hormone primarily stimulates appetite?

Ghrelin is recognized as the primary hormone that stimulates appetite. It is often referred to as the "hunger hormone" because it is produced in the stomach and its levels increase when the stomach is empty. When released into the bloodstream, ghrelin signals the brain, particularly the hypothalamus, to increase appetite and food intake. Additionally, ghrelin plays a role in enhancing the motivation to search for food, making it a key player in regulating energy balance and hunger.

Leptin, on the other hand, is involved in the regulation of energy balance but primarily functions to suppress hunger and promote satiety, particularly following meals when fat stores are sufficient. Insulin is a hormone that helps regulate blood glucose levels and also plays a role in signaling satiety rather than stimulating appetite. Peptide YY is another hormone produced in the intestines that promotes feelings of fullness after eating, thus working in opposition to appetite stimulation.

Understanding the specific roles of these hormones is crucial in the study of appetite regulation and metabolic health, emphasizing the significance of ghrelin's impact on hunger.