Which hormone is known to increase appetite and is released by the stomach?

The hormone that is known to increase appetite and is released by the stomach is ghrelin. Ghrelin is often referred to as the "hunger hormone" because it plays a critical role in signaling hunger to the brain. When the stomach is empty, ghrelin levels rise, stimulating appetite and encouraging food intake. As food is consumed and the stomach stretches, ghrelin production decreases, which helps signal satiety to the individual.

Understanding the role of ghrelin is important in discussions of nutrition and metabolism, as it can influence eating behaviors and energy balance. This hormone's action contrasts with other hormones involved in appetite regulation. For example, insulin is involved in glucose metabolism and can promote satiety when blood sugar levels are high, while leptin, produced by adipose (fat) tissue, signals fullness and regulates energy balance when fat stores are sufficient. Cortisol, a stress hormone, can affect appetite but is not directly involved in the physiological appetite signaling process initiated by the stomach, as ghrelin is.

This distinction highlights ghrelin's unique role among these hormones in regulating hunger and food intake.