Abstract
The growth hormone and appetite are regulated by a 28-peptide hormone called ghrelin, which is produced in the stomach, pituitary gland, and other body tissues. The physiological roles fulfilled by ghrelin include regulation of food intake, cardiac output, reproductive system, proliferation of cells, and formation of osteoblasts, as well as action against inflammation/fibrosis. The ghrelin present in the body can be distinguished as acylated ghrelin and deacylated ghrelin. Furthermore, both in humans and other animals, the entirety of the gastrointestinal tract comprises ghrelin cells, which are classified as open-type and closed-type cells. The present study reviews the evidence about how ghrelin cells are distributed in the human and the animal body.