What hormone is primarily responsible for the sensation of satiation?

The hormone primarily responsible for the sensation of satiation is PYY, or peptide YY. PYY is secreted by the intestinal cells in response to food intake, particularly after meals that are high in calories. Its primary role is to signal the brain to reduce appetite and increase feelings of fullness.

When food is consumed, PYY is released into the bloodstream and travels to the hypothalamus in the brain, where it acts as a signaling molecule to indicate that the body has enough energy. This process helps regulate food intake and maintain energy balance by promoting the feeling of satiation after eating.

In contrast, ghrelin is often referred to as the "hunger hormone," as it stimulates appetite, while leptin is more associated with long-term energy balance and signals that the body has sufficient energy stores. Amylin, another hormone involved in glucose metabolism, supports the actions of insulin but is not primarily responsible for the sensation of fullness in the same way that PYY is.