Ghrelin

Ghrelin is a peptide hormone primarily produced in the stomach, known for its role in regulating appetite and promoting food intake.

Function

Ghrelin acts as a hunger hormone, signaling the brain to increase hunger and stimulate the release of growth hormone. It binds to receptors in the hypothalamus, regulating energy balance, food intake, and body weight.

Production

Ghrelin is primarily secreted by specialized cells lining the fundus of the stomach, called P/D1 cells. It is released into the bloodstream and reaches various organs, affecting their functions.

Appetite Regulation

Ghrelin stimulates the appetite by targeting specific brain regions involved in hunger control. It promotes the activation of neuropeptide Y (NPY) neurons and inhibits pro-opiomelanocortin (POMC) neurons, both of which play critical roles in appetite regulation.

Metabolism and Energy Balance

By interacting with the hypothalamus and other brain areas, ghrelin influences metabolism and energy expenditure. It increases the intake of high-calorie foods and decreases fat utilization, thereby promoting weight gain and reducing energy expenditure.

Other Functions

Aside from its role in appetite regulation, ghrelin has been found to affect various physiological processes, including glucose metabolism, gastrointestinal motility, cardiovascular function, and even cognitive function.